How has quantum mechanics influenced culture in the last 100 years?

Quantum physics offers an opportunity to make the impossible seem plausible. For instance, if your superhero dies dramatically but the actor is still on the payroll, you have a few options available. You could pretend the hero miraculously survived the calamity of the previous instalment. You could also pretend the events of the previous instalment never happened. And then there is Star Wars: “Somehow, Palpatine returned.”

These days, however, quantum physics tends to come to the rescue. Because quantum physics offers the wonderful option to maintain that all previous events really happened, and yet your hero is still alive… in a parallel universe. Much is down to the remarkable cultural impact of the many-worlds interpretation of quantum physics, which has been steadily growing in fame (or notoriety) since Hugh Everett introduced it
in 1957.

Is quantum physics unique in helping fiction authors make the impossible seem possible?

Not really! Before the “quantum” handwave, there was “nuclear”: think of Dr Atomic from Watchmen, or Godzilla, as expressions of the utopian and dystopian expectations of that newly discovered branch of science. Before nuclear, there was electricity, with Frankenstein’s monster as perhaps its most important product. We can go all the way back to the invention of hydraulics in the ancient world, which led to an explosion of tales of liquid-operated automata – early forms of artificial intelligence – such as the bronze soldier Talos in ancient Greece. We have always used our latest discoveries to dream of a future in which our ancient tales of wonder could come true.

Is the many-worlds interpretation the most common theory used in science fiction inspired by quantum mechanics?

Many-worlds has become Marvel’s favourite trope. It allows them to expand on an increasingly entangled web of storylines that borrow from a range of remakes and reboots, as well as introducing gender and racial diversity into old stories. Marvel may have mainstreamed this interpretation, but the viewers of the average blockbuster may not realise exactly how niche it is, and how many alternatives there are. With many interpretations vying for acceptance, every once in a while a brave social scientist ventures to survey quantum-physicists’ preferences. These studies tend to confirm the dominance of the Copenhagen interpretation, with its collapse of the wavefunction rather than the branching universes characteristic of the Everett interpretation. In a 2016 study, for instance, only 6% of quantum physicists claimed that Everett was their favourite interpretation. In 2018 I looked through a stack of popular quantum-physics books published between 1980 and 2017, and found that more than half of these books endorse the many-worlds interpretation. A non-physicist might be forgiven for thinking that quantum physicists are split between two equal-sized enemy camps of Copenhagenists and Everettians.

What makes the many-worlds interpretation so compelling?

Answering this brings us to a fundamental question that fiction has enjoyed exploring since humans first told each other stories: what if? “What if the Nazis won the Second World War?” is pretty much an entire genre by itself these days. Before that, there were alternate histories of the American Civil War and many other key historical events. This means that the many-worlds interpretation fits smoothly into an existing narrative genre. It suggests that these alternate histories may be real, that they are potentially accessible to us and simply happening in a different dimension. Even the specific idea of branching alternative universes existed in fiction before Hugh Everett applied it to quantum mechanics. One famous example is the 1941 short story The Garden of Forking Paths by the Argentinian writer Jorge Luis Borges, in which a writer tries to create a novel in which everything that could happen, happens. His story anticipated the many-worlds interpretation so closely that Bryce DeWitt used an extract from it as the epigraph to his 1973 edited collection The Many-Worlds Interpretation of Quantum Mechanics. But the most uncanny example is, perhaps, Andre Norton’s science-fiction novel The Crossroads of Time, from 1956 – published when Everett was writing his thesis. In her novel, a group of historians invents a “possibility worlds” theory of history. The protagonist, Blake Walker, discovers that this theory is true when he meets a group of men from a parallel universe who are on the hunt for a universe-travelling criminal. Travelling with them, Blake ends up in a world where Hitler won the Battle of Britain. Of course, in fiction, only worlds in which a significant change has taken place are of any real interest to the reader or viewer. (Blake also visits a world inhabited by metal dinosaurs.) The truly uncountable number of slightly different universes Everett’s theory implies are extremely difficult to get our heads around. Nonetheless, our storytelling mindsets have long primed us for a fascination with the many-worlds interpretation.

Have writers put other interpretations to good use?

For someone who really wants to put their physics degree to use in their spare time, I’d recommend the works of Greg Egan: although his novel Quarantine uses the controversial conscious collapse interpretation, he always ensures that the maths checks out. Egan’s attitude towards the scientific content of his novels is best summed up by a quote on his blog: “A few reviewers complained that they had trouble keeping straight [the science of his novel Incandescence]. This leaves me wondering if they’ve really never encountered a book that benefits from being read with a pad of paper and a pen beside it, or whether they’re just so hung up on the idea that only non-fiction should be accompanied by note-taking and diagram-scribbling that it never even occurred to them to do this.”

What other quantum concepts are widely used and abused?

We have Albert Einstein to thank for the extremely evocative description of quantum entanglement as “spooky action at a distance”. As with most scientific phenomena, a catchy nickname such as this one is extremely effective for getting a concept to stick in the popular imagination. While Einstein himself did not initially believe quantum entanglement could be a real phenomenon, as it would violate local causality, we now have both evidence and applications of entanglement in the real world, most notably in quantum cryptography. But in science fiction, the most common application of quantum entanglement is in faster-than-light communication. In her 1966 novel Rocannon’s World, Ursula K Le Guin describes a device called the “ansible”, which interstellar travellers use to instantaneously communicate with each other across vast distances. Her term was so influential that it now regularly appears in science fiction as a widely accepted name for a faster-than-light communications device, the same way we have adopted the word “robot” from the 1920 play R.U.R. by Karel Čapek.

Fiction may get the science wrong, but that is often because the story it tries to tell existed long before the science

How were cultural interpretations of entanglement influenced by the development of quantum theory?

It wasn’t until the 1970s that no-signalling theorems conclusively proved that entanglement correlations, while instantaneous, cannot be controlled or used to send messages. Explaining why is a lot more complex than communicating the notion that observing a particle here has an effect on a particle there. Once again, quantum physics seemingly provides just enough scientific justification to resolve an issue that has plagued science fiction ever since the speed of light was discovered: how can we travel through space, exploring galaxies, settling on distant planets, if we cannot communicate with each other? This same line of thought has sparked another entanglement-related invention in fiction: what if we can send not just messages but also people, or even entire spaceships, across faster-than-light distances using entanglement? Conveniently, quantum physicists had come up with another extremely evocative term that fit this idea perfectly: quantum teleportation. Real quantum teleportation only transfers information. But the idea of teleportation is so deeply embedded in our storytelling past that we can’t help extrapolating it. From stories of gods that could appear anywhere at will to tales of portals that lead to strange new worlds, we have always felt limited by the speeds of travel we have managed to achieve – and once again, the speed of light seems to be a hard limit that quantum teleportation might be able to get us around. In his 2003 novel Timeline, Michael Crichton sends a group of researchers back in time using quantum teleportation, and the videogame Half-Life 2 contains teleportation devices that similarly seem to work through quantum entanglement.

What quantum concepts have unexplored cultural potential?

Clearly, interpretations other than many worlds have a PR problem, so is anyone willing to write a chart topper based on the relational interpretation or QBism? More generally, I think that any question we do not yet have an answer to, or any theory that remains untestable, is a potential source for an excellent story. Richard Feynman famously said, “I think I can safely say that nobody understands quantum mechanics.” Ironically, it is precisely because of this that quantum physics has become such a widespread building block of science fiction: it is just hard enough to understand, just unresolved and unexplained enough to keep our hopes up that one day we might discover that interstellar communication or inter-universe travel might be possible. Few people would choose the realities of theorising over these ancient dreams. That said, the theorising may never have happened without the dreams. How many of your colleagues are intimately acquainted with the very science fiction they criticise for having unrealistic physics? We are creatures of habit and convenience held together by stories, physicists no less than everyone else. This is why we come up with catchy names for theories, and stories about dead-and-alive cats. Fiction may often get the science wrong, but that is often because the story it tries to tell existed long before the science.

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The boundary between industry and academia can feel like a chasm. Opportunity abounds for those willing to bridge the gap.

Massimiliano Pindo began his career working on silicon pixel detectors at the DELPHI experiment at the Large Electron–Positron Collider. While at CERN, Pindo developed analytical and technical skills that would later become crucial in his career. But despite his passion for research, doubts clouded his hopes for the future.

“I wanted to stay in academia,” he recalls. “But at that time, it was getting really difficult to get a permanent job.” Pindo moved from his childhood home in Milan to Geneva, before eventually moving back in with his parents while applying for his next research grant. “The golden days of academia where people got a fixed position immediately after a postdoc or PhD were over.”

The path forward seemed increasingly unstable, defined by short-term grants, constant travel and an inability to plan long-term. There was always a constant stream of new grant applications, but permanent contracts were few and far between. With competition increasing, job stability seemed further and further out of reach. “You could make a decent living,” Pindo says, “but the real problem was you could not plan your life.”

Translatable skills

Faced with the unpredictability of academic work, Pindo transitioned into industry – a leap that eventually led him to his current role as marketing and sales director at Renishaw, France, a global engineering and scientific technology company. Pindo was confident that his technical expertise would provide a strong foundation for a job beyond academia, and indeed he found that “hard” skills such as analytical thinking, problem-solving and a deep understanding of technology, which he had honed at CERN alongside soft skills such as teamwork, languages and communication, translated well to his work in industry.

“When you’re a physicist, especially a particle physicist, you’re used to breaking down complex problems, selecting what is really meaningful amongst all the noise, and addressing these issues directly,” Pindo says. His experience in academia gave him the confidence that industry challenges would pale in comparison. “I was telling myself that in the academic world, you are dealing with things that, at least on paper, are more complex and difficult than what you find in industry.”

Initially, these technical skills helped Pindo become a device engineer for a hardware company, before making the switch to sales. The gradual transition from academia to something more hands-on allowed him to really understand the company’s product on a technical level, which made him a more desirable candidate when transitioning into marketing.

“When you are in B2B [business-to-business] mode and selling technical products, it’s always good to have somebody who has technical experience in the industry,” explains Pindo. “You have to have a technical understanding of what you’re selling, to better understand the problems customers are trying to solve.”

However, this experience also allowed him to recognise gaps in his knowledge. As he began gaining more responsibility in his new, more business-focused role, Pindo decided to go back to university and get an MBA. During the programme, he was able to familiarise himself with the worlds of human resources, business strategy and management – skills that aren’t typically the focus in a physics lab.

Pindo’s journey through industry hasn’t been a one-way ticket out of academia. Today, he still maintains a foothold in the academic world, teaching strategy as an affiliated professor at the Sorbonne. “In the end you never leave the places you love,” he says. “I got out through the door – now I’m getting back in through the window!”

Transitioning between industry and academia was not entirely seamless. Misconceptions loomed on both sides, and it took Pindo a while to find a balance between the two.

“There is a stereotype that scientists are people who can’t adapt to industrial environments – that they are too abstract, too theoretical,” Pindo explains. “People think scientists are always in the clouds, disconnected from reality. But that’s not true. The science we make is not the science of cartoons. Scientists can be people who plan and execute practical solutions.”

The misunderstanding, he says, goes both ways. “When I talk to alumni still in academia, many think that industry is a nightmare – boring, routine, uninteresting. But that’s also false,” Pindo says. “There’s this wall of suspicion. Academics look at industry and think, ‘What do they want? What’s the real goal? Are they just trying to make more money?’ There is no trust.”

Tight labour markets

For Pindo, this divide is frustrating and entirely unnecessary. Now with years of experience navigating both worlds, he envisions a more fluid connection between academia and industry – one that leverages the strengths of both. “Industry is currently facing tight labour markets for highly skilled talent, and academia doesn’t have access to the money and practical opportunities that industry can provide,” says Pindo. “Both sides need to work together.”

To bridge this gap, Pindo advocates a more open dialogue and a revolving door between the two fields – one that allows both academics and industry professionals to move fluidly back and forth, carrying their expertise across boundaries. Both sides have much to gain from shared knowledge and collaboration. One way to achieve this, he suggests, is through active participation in alumni networks and university events, which can nurture lasting relationships and mutual understanding. If more professionals embraced this mindset, it could help alleviate the very instability that once pushed him out of academia, creating a landscape where the boundaries between science and industry blur to the benefit of both.

“Everything depends on active listening. You always have to learn from the person in front of you, so give them the chance to speak. We have a better world to build, and that comes only from open dialogue and communication.”

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Mary K was a theoretical physicist of great power, gifted both with a deep physical intuition and a very high level of technical mastery. She used her gifts to great effect and made many important contributions to the development of the Standard Model of elementary particle physics that was established precisely during the course of her career. She pursued her love of physics with powerful determination, in the face of overt discrimination that went well beyond what may still exist today. She fought these battles and produced beautiful, important physics, all while raising three children as a devoted mother.

Undeniable impact

After obtaining her master’s degree at Columbia, Mary K accompanied her first husband, Jean-Marc Gaillard, to Paris, where she was rebuffed in many attempts to obtain a position in an experimental group. She next tried and failed, multiple times, to find an advisor in theoretical physics, which she actually preferred to experimental physics but had not pursued because it was regarded as an even more unlikely career for a woman. Eventually, and fortunately for the development of elementary particle physics, Bernard d’Espagnat agreed to supervise her doctoral research at the University of Paris. While she quickly succeeded in producing significant results in her research, respect and recognition were still slow to come. She suffered many slights from a culture that could not understand or countenance the possibility of a woman theoretical physicist and put many obstacles in her way. Respect and recognition did finally come in appropriate measure, however, by virtue of the undeniable impact of her work.

Her contributions to the field are numerous. During an intensely productive period in the mid-1970s, she completed a series of projects that established the framework for the decades to follow that would culminate in the Standard Model. Famously, during a one-year visit to Fermilab in 1973, using the known properties of the “strange” K mesons, she successfully predicted the mass scale of the fourth “charm” quark a few months prior to its discovery. Back at CERN a few years later, she also predicted, in the framework of grand unified theories, the mass of the fifth “bottom” quark – a successful though still speculative prediction. Other impactful work, extracting the experimental consequences of theoretical constructs, laid down the paths that were followed to experimentally validate the charm-quark discovery and to search for the Higgs boson required to complete the Standard Model. Another key contribution showed how “jets”, streams of particles created in high-energy accelerators, could be identified as manifestations of the “gluon” carriers of the strong force of the Standard Model.

In the 1980s in Berkeley, when the Superconducting Super Collider and the Large Hadron Collider were under discussion, she showed that they could successfully uncover the mechanism of electroweak symmetry breaking required to understand the Standard Model weak force, even if it was “dynamical” – an experimentally much more challenging possibility than breaking by a Higgs boson. For the remainder of her career, she focused principally on work to address issues that are still unresolved by the Standard Model. Much of this research involved “supersymmetry” and its extension to encompass the gravitational force, theoretical constructs that originated in the work of her second husband, the late Bruno Zumino, who also moved from CERN to Berkeley.

Mary K’s accomplishments were recognised by numerous honorary societies and awards, including the National Academy of Sciences, the American Academy of Arts and Sciences, and the J. J. Sakurai Prize for Theoretical Particle Physics of the American Physical Society. She served on numerous governmental and academic advisory panels, including six years on the National Science Board. She tells her own story in a memoir, A Singularly Unfeminine Profession, published in 2015. Mary K Gaillard will surely be remembered when the final history of elementary particle physics is written.

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Born in Bonn, Germany in 1950, Fritz studied electrical engineering at RWTH Aachen. He joined CERN in 1981, first as a fellow and then as a staff member. During the 1980s Fritz contributed to stochastic cooling in CERN’s antiproton programme. In the team of Georges Carron and Lars Thorndahl, he helped devise ultra-fast microwave stochastic cooling systems for the then new antiproton cooler ring. He also initiated the development of power field-effect transistors that are still operational today in CERN’s Antiproton Decelerator ring. Fritz conceived novel geometries for pickups and kickers, such as slits cut into ground plates, as now used for the GSI FAIR project, and meander-type electrodes. From 1988 to 1995, Fritz was responsible for all 26 stochastic-cooling systems at CERN. In 1990 he became a senior member of the Institute of Electrical and Electronics Engineers (IEEE), before being distinguished as an IEEE Life Fellow later in his career.

Pioneering diagnostics

In the mid-2000s, Fritz proposed enamel-based clearing electrodes and initiated pertinent collaborations with several German companies. At about the same time, he carried out ultrasound diagnostics on soldered junctions on LHC interconnects. Among the roughly 1000 junctions measured, he and his team found a single non-conform junction. In 2008 Fritz suggested non-elliptical superconducting crab cavities for the HL-LHC. He also proposed and performed pioneering electron-cloud diagnostics and mitigation-using microwaves. For the LHC, he predicted a “magnetron effect”, where coherently radiating cloud electrons might quench the LHC magnets at specific values of their magnetic field. His advice was highly sought after on laboratory-impedance measurements and electromagnetic interference.

Throughout the past three decades, Fritz was active and held in high esteem not only at CERN but all around the world. For example, he helped develop the stochastic cooling systems for GSI in Darmstadt, Germany, where his main contact was Fritz Nolden. He contributed to the construction and commissioning of stochastic cooling for GSI’s Experimental Storage Ring, including the successful demonstration of the stochastic cooling of heavy ions in 1997. Fritz also helped develop the stochastic cooling of rare isotopes for the RI Beam Factory project at RIKEN, Japan.

He helped develop the power field-effect transistors still operational today in CERN’s AD ring

Fritz was a long-term collaborator of IMP Lanzhou at the Chinese Academy of Sciences (CAS). In 2015, stochastic cooling was commissioned at the Cooling Storage Ring with his support. Always kind and willing to help anyone who needed him, Fritz also provided valuable suggestions and hands-on experience with impedance measurements for IMP’s HIAF project, especially the titanium-alloy-loaded thin-wall vacuum chamber and magnetic-alloy-loaded RF cavities. In 2021, Fritz was elected as a Distinguished Scientist of the CAS President’s International Fellowship Initiative and awarded the Dieter Möhl Award by the International Committee for Future Accelerators for his contributions to beam cooling.

In 2013, the axion dark-matter research centre IBS-CAPP was established at KAIST, Korea. For this new institute, Fritz proved to be just the right lecturer. Every spring, he visited Korea for a week of intensive lectures on RF techniques, noise measurements and much more. His lessons, which were open to scientists from all over Korea, transformed Korean researchers from RF amateurs into professionals, and his contributions helped propel IBS–CAPP to the forefront of research.

Fritz was far more than just a brilliant scientist. He was a generous mentor, a trusted colleague and a dear friend who lit up a room when he entered, and his absence will be deeply felt by all of us who had the privilege of knowing him. Always on the hunt for novel ideas, Fritz was a polymath and a fully open-minded scientist. His library at home was a visit into the unknown, containing “dark matter”, as we often joked. We will remember Fritz as a gentleman who was full of inspiration for the young and the not-so-young alike. His death is a loss to the whole accelerator world.

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Born in 1936 and raised in Kilmarnock, Scotland, Sandy received his BSc and PhD degrees from the University of Glasgow before taking up a lectureship at University College London in 1963. He was a CERN research associate from 1965 to 1967, and then senior lecturer at the University of Glasgow until 1969, when he took up a chair at the University of Manchester and played a leading role in developing the scientific programme at NINA, the electron synchrotron at the nearby Daresbury National Laboratory. Sandy then served as head of the Department of Physics and Astronomy at the University from 1989 to 1994, and as dean of the Faculty of Science and Engineering from 1994 to 1997. He had a formidable reputation – if a staff member or student asked to see him, he would invite them to come at 8 a.m., to test whether what they wanted to discuss was truly important.

Sandy played a leading role in the international scientific community, maintaining strong connections with CERN throughout his career, as scientific delegate to the CERN Council from 1989 to 1994, chair of the SPS committee from 1988 to 1992, and member of the CERN Scientific Policy Committee from 1988 to 1993. In the UK, he chaired the UK’s Nuclear Physics Board from 1989 to 1993, and served as a member of the Science and Engineering Research Council from 1989 to 1994. He also served as an associate editor for Physical Review Letters from 2010 to 2016. In recognition of his leadership and scientific contributions, he was awarded the UK’s Institute of Physics Glazebrook Medal in 1997.

The “Donnachie–Landshoff pomeron” is known to all those working in the field

Sandy is perhaps best known for his body of work with Peter Landshoff on elastic and diffractive scattering: the “Donnachie–Landshoff pomeron” is known to all those
working in the field. The collaboration began half a century ago and when email became available, they were among its early and most enthusiastic users. Sandy only knew Fortran and Peter only knew C, but somehow they managed to collaborate and together wrote more than 50 publications, including a book Pomeron Physics and QCD with Günter Dosch and Otto Nachtmann published in 2004. The collaboration lasted until, so sadly, Sandy was struck with Parkinson’s disease and was no longer able to use email. Earlier in his career, Sandy had made significant contributions to the field of low-energy hadron scattering, in particular through a collaboration with Claud Lovelace, which revealed many hitherto unknown baryon states in pion–nucleon scattering, and through a series of papers on meson photoproduction, initially with Graham Shaw and then with Frits Berends and other co-workers.

Throughout his career, Sandy was notable for his close collaborations with experimental physics groups, including a long association with the Omega Photon Collaboration at CERN, with whom he co-authored 27 published papers. He and Shaw also produced three books, culminating in Electromagnetic Interactions and Hadronic Structure with Frank Close, which was published in 2007.

In his leisure time, Sandy was a great lover of classical music and a keen sailor, golfer and country walker.

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Born in Reutlingen, Germany, on 5 April 1933, Fritz obtained his electrical engineering degree in Stuttgart and a doctorate at the University of Grenoble. A contract with General Electric in his pocket, he visited CERN, curious about the 25 GeV Proton Synchrotron, the construction of which was receiving the finishing touches in the late 1950s. He met senior CERN staff and was offered a contract that he, impressed by the visit, accepted in early 1959.

Fritz’s first assignment was the development of a radio-frequency (RF) accelerating cavity for a planned fixed-field alternating-gradient (FFAG) accelerator. This was abandoned in early 1960 in favour of the study of a 2 × 25 GeV proton–proton collider, the Intersecting Storage Rings (ISR). As a first step, the CERN Electron Storage and Accumulation Ring (CESAR) was constructed to test high-vacuum technology and RF accumulation schemes; Fritz designed and constructed the RF system. With CESAR in operation, he moved on to the construction and tests of the high-power RF system of the ISR, a project that was approved in 1965.

After the smooth running-in of the ISR and, for a while having been responsible for the General Engineering Group, he became division leader of the ISR in 1974, a position he held until 1982. Under his leadership the ISR unfolded its full potential with proton beam currents up to 50 A and a luminosity 35 times the design value, leading CERN to acquire the confidence that colliders were the way to go. Due to his foresight, the development of new technologies was encouraged for the accelerator, including superconducting quadrupoles and pumping by cryo- and getter surfaces. Both were applied on a grand scale in LEP and are still essential for the LHC today.

Under his ISR leadership CERN acquired the confidence that colliders were the way to go

When the resources of the ISR Division were refocussed on LEP in 1983, Fritz became the leader of the Technical Inspection and Safety Commission. This absorbed the activities of the previous health and safety groups, but its main task was to scrutinise the LEP project from all technical and safety aspects. Fritz’s responsibility widened considerably when he became leader of the Technical Support Division in 1986. All of the CERN civil engineering, the tunnelling for the 27 km circumference LEP ring, its auxiliary tunnels, the concreting of the enormous caverns for the experiments and the construction of a dozen surface buildings were in full swing and brought to a successful conclusion in the following years. New buildings on the Meyrin site were added, including the attractive Building 40 for the large experimental groups, in which he took particular pride. At the same time, and under pressure to reduce expenditure, he had to manage several difficult outsourcing contracts.

When he retired in 1997, he could look back on almost 40 years dedicated to CERN; his scientific and technical competence paired with exceptional organisational and administrative talent. We shall always remember him as an exacting colleague with a wide range of interests, and as a friend, appreciated for his open and helpful attitude.

We grieve his loss and offer our sincere condolences to his widow Catherine and their daughters Sophie and Karina.

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DESY is a large laboratory with just over 3000 employees. It was founded 65 years ago as an accelerator lab, and at its heart it remains one, though what we do with the accelerators has evolved over time. It is fully funded by Germany.

In particle physics, DESY has performed many important studies, for example to understand the charm quark following the November Revolution of 1974. The gluon was discovered here in the late 1970s. In the 1980s, DESY ran the first experiments to study B mesons, laying the groundwork for core programmes such as LHCb at CERN and the Belle II experiment in Japan. In the 1990s, the HERA accelerator focused on probing the structure of the proton, which, incidentally, was the subject of my PhD, and those results have been crucial for precision studies of the Higgs boson.

Over time, DESY has become much more than an accelerator and particle-physics lab. Even in the early days, it used what is called synchrotron radiation, the light emitted when electrons change direction in the accelerator. This light is incredibly useful for studying matter in detail. Today, our accelerators are used primarily for this purpose: they generate X-rays that image tiny structures, for example viruses.

DESY’s culture is shaped by its very engaged and loyal workforce. People often call themselves “DESYians” and strongly identify with the laboratory. At its heart, DESY is really an engineering lab. You need an amazing engineering workforce to be able to construct and operate these accelerators.

Which of DESY’s scientific achievements are you most proud of?

The discovery of the gluon is, of course, an incredible achievement, but actually I would say that DESY’s greatest accomplishment has been building so many cutting-edge accelerators: delivering them on time, within budget, and getting them to work as intended.

Take the PETRA accelerator, for example – an entirely new concept when it was first proposed in the 1970s. The decision to build it was made in 1975; construction was completed by 1978; and by 1979 the gluon was discovered. So in just four years, we went from approving a 2.3 km accelerator to making a fundamental discovery, something that is absolutely crucial to our understanding of the universe. That’s something I’m extremely proud of.

I’m also very proud of the European X-ray Free-Electron Laser (XFEL), completed in 2017 and now fully operational. Before that, in 2005 we launched the world’s first free-electron laser, FLASH, and of course in the 1990s HERA, another pioneering machine. Again and again, DESY has succeeded in building large, novel and highly valuable accelerators that have pushed the boundaries of science.

What can we look forward to during your time as chair?

We are currently working on 10 major projects in the next three years alone! PETRA III will be running until the end of 2029, but our goal is to move forward with PETRA IV, the world’s most advanced X-ray source. Securing funding for that first, and then building it, is one of my main objectives. In Germany, there’s a roadmap process, and by July this year we’ll know whether an independent committee has judged PETRA IV to be one of the highest-priority science projects in the country. If all goes well, we aim to begin operating PETRA IV in 2032.

Our FLASH soft X-ray facility is also being upgraded to improve beam quality, and we plan to relaunch it in early September. That will allow us to serve more users and deliver better beam quality, increasing its impact.

In parallel, we’re contributing significantly to the HL-LHC upgrade. More than 100 people at DESY are working on building trackers for the ATLAS and CMS detectors, and parts of the forward calorimeter of CMS. That work needs to be completed by 2028.

Astroparticle physics is another growing area for us. Over the next three years we’re completing telescopes for the Cherenkov Telescope Array and building detectors for the IceCube upgrade. For the first time, DESY is also constructing a space camera for the satellite UltraSat, which is expected to launch within the next three years.

At the Hamburg site, DESY is diving further into axion research. We’re currently running the ALPS II experiment, which has a fascinating “light shining through a wall” setup. Normally, of course, light can’t pass through something like a thick concrete wall. But in ALPS II, light inside a magnet can convert into an axion, a hypothetical dark-matter particle that can travel through matter almost unhindered. On the other side, another magnet converts the axion back into light. So, it appears as if the light has passed through the wall, when in fact it was briefly an axion. We started the experiment last year. As with most experiments, we began carefully, because not everything works at once, but two more major upgrades are planned in the next two years, and that’s when we expect ALPS II to reach its full scientific potential.

We’re also developing additional axion experiments. One of them, in collaboration with CERN, is called BabyIAXO. It’s designed to look for axions from the Sun, where you have both light and magnetic fields. We hope to start construction before the end of the decade.

Finally, DESY also has a strong and diverse theory group. Their work spans many areas, and it’s exciting to see what ideas will emerge from them over the coming years.

How does DESY collaborate with industry to deliver benefits to society?

We already collaborate quite a lot with industry. The beamlines at PETRA, in particular, are of strong interest. For example, BioNTech conducted some of its research for the COVID-19 vaccine here. We also have a close relationship with the Fraunhofer Society in Germany, which focuses on translating basic research into industrial applications. They famously developed the MP3 format, for instance. Our collaboration with them is quite structured, and there have also been several spinoffs and start-ups based on technology developed at DESY. Looking ahead, we want to significantly strengthen our ties with industry through PETRA IV. With much higher data rates and improved beam quality, it will be far easier to obtain results quickly. Our goal is for 10% of PETRA IV’s capacity to be dedicated to industrial use. Furthermore, we are developing a strong ecosystem for innovation on the campus and the surrounding area, with DESY in the centre, called the Science City Hamburg Bahrenfeld.

What’s your position on “dual use” research, which could have military applications?

The discussion around dual-use research is complicated. Personally, I find the term “dual use” a bit odd – almost any high-tech equipment can be used for both civilian and military purposes. Take a transistor for example, which has countless applications, including military ones, but it wasn’t invented for that reason. At DESY, we’re currently having an internal discussion about whether to engage in projects that relate to defence. This is part of an ongoing process where we’re trying to define under what conditions, if any, DESY would take on targeted projects related to defence. There are a range of views within DESY, and I think that diversity of opinion is valuable. Some people are firmly against this idea, and I respect that. Honestly, it’s probably how I would have felt 10 or 20 years ago. But others believe DESY should play a role. Personally, I’m open to it.

If our expertise can help people defend themselves and our freedom in Europe, that’s something worth considering. Of course, I would love to live in a world without weapons, where no one attacks anyone. But if I were attacked, I’d want to be able to defend myself. I prefer to work on shields, not swords, like in Asterix and Obelix, but, of course, it’s never that simple. That’s why we’re taking time with this. It’s a complex and multifaceted issue, and we’re engaging with experts from peace and security research, as well as the social sciences, to help us understand all dimensions. I’ve already learned far more about this than I ever expected to. We hope to come to a decision on this later this year.

You are DESY’s first female chair. What barriers do you think still exist for women in physics, and how can institutions like DESY address them?

There are two main barriers, I think. The first is that, in my opinion, society at large still discourages girls from going into maths and science.

Certainly in Germany, if you stopped a hundred people on the street, I think most of them would still say that girls aren’t naturally good at maths and science. Of course, there are always exceptions: you do find great teachers and supportive parents who go against this narrative. I wouldn’t be here today if I hadn’t received that kind of encouragement.

That’s why it’s so important to actively counter those messages. Girls need encouragement from an early age, they need to be strengthened and supported. On the encouragement side, DESY is quite active. We run many outreach activities for schoolchildren, including a dedicated school lab. Every year, more than 13,000 school pupils visit our campus. We also take part in Germany’s “Zukunftstag”, where girls are encouraged to explore careers traditionally considered male-dominated, and boys do the same for fields seen as female-dominated.

Looking ahead, we want to significantly strengthen our ties with industry

The second challenge comes later, at a different career stage, and it has to do with family responsibilities. Often, family work still falls more heavily on women than men in many partnerships. That imbalance can hold women back, particularly during the postdoc years, which tend to coincide with the time when many people are starting families. It’s a tough period, because you’re trying to advance your career.

Workplaces like DESY can play a role in making this easier. We offer good childcare options, flexibility with home–office arrangements, and even shared leadership positions, which help make it more manageable to balance work and family life. We also have mentoring programmes. One example is dynaMENT, where female PhD students and postdocs are mentored by more senior professionals. I’ve taken part in that myself, and I think it’s incredibly valuable.

Do you have any advice for early-career women physicists?

If I could offer one more piece of advice, it’s about building a strong professional network. That’s something I’ve found truly valuable. I’m fortunate to have a fantastic international network, both male and female colleagues, including many women in leadership positions. It’s so important to have people you can talk to, who understand your challenges, and who might be in similar situations. So if you’re a student, I’d really recommend investing in your network. That’s very important, I think.

What are your personal reflections on the next-generation colliders?

Our generation has a responsibility to understand the electroweak scale and the Higgs boson. These questions have been around for almost 90 years, since 1935 when Hideki Yukawa explored the idea that forces might be mediated by the exchange of massive particles. While we’ve made progress, a true understanding is still out of reach. That’s what the next generation of machines is aiming to tackle.

The problem, of course, is cost. All the proposed solutions are expensive, and it is very challenging to secure investments for such large-scale projects, even though the return on investment from big science is typically excellent: these projects drive innovation, build high-tech capability and create a highly skilled workforce.

Europe’s role is more vital than ever

From a scientific point of view, the FCC is the most comprehensive option. As a Higgs factory, it offers a broad and strong programme to analyse the Higgs and electroweak gauge bosons. But who knows if we’ll be able to afford it? And it’s not just about money. The timeline and the risks also matter. The FCC feasibility report was just published and is still under review by an expert committee. I’d rather not comment further until I’ve seen the full information. I’m part of the European Strategy Group and we’ll publish a new report by the end of the year. Until then, I want to understand all the details before forming an opinion.

It’s good to have other options too. The muon collider is not yet as technically ready as the FCC or linear collider, but it’s an exciting technology and could be the machine after next. Another could be using plasma-wakefield acceleration, which we’re very actively working on at DESY. It could enable us to build high-energy colliders on a much smaller scale. This is something we’ll need, as we can’t keep building ever-larger machines forever. Investing in accelerator R&D to develop these next-gen technologies is crucial.

Still, I really hope there will be an intermediate machine in the near future, a Higgs factory that lets us properly explore the Higgs boson. There are still many mysteries there. I like to compare it to an egg: you have to crack it open to see what’s inside. And that’s what we need to do with the Higgs.

One thing that is becoming clearer to me is the growing importance of Europe. With the current uncertainties in the US, which are already affecting health and climate research, we can’t assume fundamental research will remain unaffected. That’s why Europe’s role is more vital than ever.

I think we need to build more collaborations between European labs. Sharing expertise, especially through staff exchanges, could be particularly valuable in engineering, where we need a huge number of highly skilled professionals to deliver billion-euro projects. We’ve got one coming up ourselves, and the technical expertise for that will be critical.

I believe science has a key role to play in strengthening Europe, not just culturally, but economically too. It’s an area where we can and should come together.

The post Charting DESY’s future appeared first on CERN Courier.

In the past decade, machine learning has surged into every corner of industry, from travel and transport to healthcare and finance. For early-career researchers, who have spent their PhDs and postdocs coding, a job in machine learning may seem a natural next step.

“Scientists often study nature by attempting to model the world around us into math­ematical models and computer code,” says Antoni Shtipliyski, engineering manager at Skyscanner. “But that’s only one part of the story if the aim is to apply these models to large-scale research questions or business problems. A completely orthogonal set of challenges revolves around how people collaborate to build and operate these systems. That’s where the real work begins.”

Used to large-scale experiments and collaborative problem solving, particle physicists are uniquely well-equipped to step into machine-learning roles. Shtipliyski worked on upgrades for the level-1 trigger system of the CMS experiment at CERN, before leaving to lead the machine-learning operations team in one of the biggest travel companies in the world.

Effective mindset

“At CERN, building an experimental detector is just the first step,” says Shtipliyski. “To be useful, it needs to be operated effectively over a long period of time. That’s exactly the mindset needed in industry.”

During his time as a physicist, Shtipliyski gained multiple skills that continue to help him at work today, but there were also a number of other areas he developed to succeed in machine learning in industry. One critical gap in a physicists’ portfolio, he notes, is that many people interpret machine-learning careers as purely algorithmic development and model training.

“At Skyscanner, my team doesn’t build models directly,” he says. “We look after the platform used to push and serve machine-learning models to our users. We oversee the techno-social machine that delivers these models to travellers. That’s the part people underestimate, and where a lot of the challenges lie.”

An important factor for physicists transitioning out of academia is to understand the entire lifecycle of a machine-learning project. This includes not only developing an algorithm, but deploying it, monitoring its performance, adapting it to changing conditions and ensuring that it serves business or user needs.

Learning to write and communicate yourself is incredibly powerful

“In practice, you often find new ways that machine-learning models surprise you,” says Shtipliyski. “So having flexibility and confidence that the evolved system still works is key. In physics we’re used to big experiments like CMS being designed 20 years before being built. By the time it’s operational, it’s adapted so much from the original spec. It’s no different with machine-learning systems.”

This ability to live with ambiguity and work through evolving systems is one of the strongest foundations physicists can bring. But large complex systems cannot be built alone, so companies will be looking for examples of soft skills: teamwork, collaboration, communication and leadership.

“Most people don’t emphasise these skills, but I found them to be among the most useful,” Shtipliyski says. “Learning to write and communicate yourself is incredibly powerful. Being able to clearly express what you’re doing and why you’re doing it, especially in high-trust environments, makes everything else easier. It’s something I also look for when I do hiring.”

Industry may not offer the same depth of exploration as academia, but it does offer something equally valuable: breadth, variety and a dynamic environment. Work evolves fast, deadlines come more readily and teams are constantly changing.

“In academia, things tend to move more slowly. You’re encouraged to go deep into one specific niche,” says Shtipliyski. “In industry, you often move faster and are sometimes more shallow. But if you can combine the depth of thought from academia with the breadth of experience from industry, that’s a winning combination.”

Applied skills

For physicists eyeing a career in machine learning, the most they can do is to familiarise themselves with tools and practices for building and deploying models. Show that you can use the skills developed in academia and apply them to other environments. This tells recruiters that you have a willingness to learn, and is a simple but effective way of demonstrating commitment to a project from start to finish, beyond your assigned work.

“People coming from physics or mathematics might want to spend more time on implementation,” says Shtipliyski. “Even if you follow a guided walkthrough online, or complete classes on Coursera, going through the whole process of implementing things from scratch teaches you a lot. This puts you in a position to reason about the big picture and shows employers your willingness to stretch yourself, to make trade-offs and to evaluate your work critically.”

A common misconception is that practicing machine learning outside of academia is somehow less rigorous or less meaningful. But in many ways, it can be more demanding.

Scientific development is often driven by arguments of beauty and robustness. In industry, there’s less patience for that,” he says. “You have to apply it to a real-world domain – finance, travel, healthcare. That domain shapes everything: your constraints, your models, even your ethics.”

Shtipliyski emphasises that the technical side of machine learning is only one half of the equation. The other half is organisational: helping teams work together, navigate constraints and build systems that evolve over time. Physicists would benefit from exploring different business domains to understand how machine learning is used in different contexts. For example, GDPR constraints make privacy a critical issue in healthcare and tech. Learning how government funding is distributed throughout each project, as well as understanding how to build a trusting relationship between the funding agencies and the team, is equally important.

“A lot of my day-to-day work is just passing information, helping people build a shared mental model,” he says. “Trust is earned by being vulnerable yourself, which allows others to be vulnerable in turn. Once that happens, you can solve almost any problem.”

Taking the lead

Particle physicists are used to working in high-stakes, international teams, so this collaborative mindset is engrained in their training. But many may not have had the opportunity to lead, manage or take responsibility for an entire project from start to finish.

“In CMS, I did not have a lot of say due to the complexity and scale of the project, but I was able to make meaningful contributions in the validation and running of the detector,” says Shtipliyski. “But what I did not get much exposure to was the end-to-end experience, and that’s something employers really want to see.”

This does not mean you need to be a project manager to gain leadership experience. Early-career researchers have the chance to up-skill when mentoring a newcomer, help improve the team’s workflow in a proactive way, or network with other physicists and think outside the box.

You can be the dedicated expert in the room, even if you’re new. That feels really empowering

“Even if you just shadow an existing project, if you can talk confidently about what was done, why it was done and how it might be done differently – that’s huge.”

Many early-career researchers hesitate prior to leaving academia. They worry about making the “wrong” choice, or being labelled as a “finance person” or “tech person” as soon as they enter another industry. This is something Shtipliyski struggled to reckon with, but eventually realised that such labels do not define you.

“It was tough at CERN trying to anticipate what comes next,” he admits. “I thought that I could only have one first job. What if it’s the wrong one? But once a scientist, always a scientist. You carry your experiences with you.”

Shtipliyski quickly learnt that industry operates under a different set of rules: where everyone comes from a different background, and the levels of expertise differ depending on the person you will speak to next. Having faced intense imposter syndrome at CERN – having shared spaces with world-leading experts – industry offered Shtipliyski a more level playing field.

“In academia, there’s a kind of ladder: the longer you stay, the better you get. In industry, it’s not like that,” says Shtipliyski. “You can be the dedicated expert in the room, even if you’re new. That feels really empowering.”

Industry rewards adaptability as much as expertise. For physicists stepping beyond academia, the challenge is not abandoning their training, but expanding it – learning to navigate ambiguity, communicate clearly and understand the full lifecycle of real-world systems. Harnessing a scientist’s natural curiosity, and demonstrating flexibility, allows the transition to become less about leaving science behind, and more about discovering new ways to apply it.

“You are the collection of your past experiences,” says Shtipliyski. “You have the freedom to shape the future.”

The post Machine learning in industry appeared first on CERN Courier.

Walter Oelert, founding spokesperson of COSY-11 and an experimentalist of rare foresight in the study of antimatter, passed away on 25 November 2024.

Walter was born in Dortmund on 14 July 1942. He studied physics in Hamburg and Heidelberg, achieving his diploma on solid-state detectors in 1969 and his doctoral thesis on transfer reactions on samarium isotopes in 1973. He spent the years from 1973 to 1975 working on transfer reactions of rare-earth elements as a postdoc in Pittsburgh under Bernie Cohen, after which he continued his nuclear-physics experiments at the Jülich cyclotron.

With the decision to build the “Cooler Synchrotron” (COSY) at Forschungszentrum Jülich (FZJ), he terminated his work on transfer reactions, summarised it in a review article, and switched to the field of medium-energy physics. At the end of 1985 he conducted a research stay at CERN, contributing to the PS185 and the JETSET (PS202) experiments at the antiproton storage ring LEAR, while also collaborating with Swedish partners at the CELSIUS synchrotron in Uppsala. In 1986 he habilitated at Ruhr University Bochum, where he was granted an APL professorship in 1996.

With the experience gained at CERN, Oelert proposed the construction of the international COSY-11 experiment as spokesperson, leading the way on studies of threshold production with full acceptance for the reaction products. From first data in 1996, COSY-11 operated successfully for 11 years, producing important results in several meson-production channels.

At CERN, Walter proposed the production of antihydrogen in the interaction of the antiproton beam with a xenon cluster target – the last experiment before the shutdown of LEAR. The experiment was performed in 1995, resulting in the production of nine antihydrogen atoms. This result was an important factor in the decision by CERN management to build the antiproton–decelerator (AD). In order to continue antihydrogen studies, he received substantial support from Jülich for a partnership in the new ATRAP experiment aiming for CPT violation studies in antihydrogen spectroscopy.

Walter retired in 2008, but kept active in antiproton activities at the AD for more than 10 years, during which time he was affiliated with the Johannes Gutenberg University of Mainz. He was one of the main driving forces on the way to the extra-low-energy antiproton ring (ELENA), which was finally built within time and financial constraints, and drastically improved the performance of the antimatter experiments. He also received a number of honours, notably the Merentibus Medal of the Jagiellonian University of Kraków, and was elected as an external member of the Polish Academy of Arts and Sciences.

Walter’s personality – driven, competent, visionary, inspiring, open minded and caring – was the type of glue that made proactive, successful and happy collaborations.

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Born in Moscow in 1941, Domogatsky obtained his PhD in 1970 from Moscow Lomonosov University and then worked at the Moscow Lebedev Institute. There, he studied the processes of the interaction of low-energy neutrinos with matter and neutrino emission during the gravitational collapse of stars. His work was essential for defining the scientific programme of the Baksan Neutrino Observatory. Already at that time, he had put forward the idea of a network of underground detectors to register neutrinos from supernovae, a programme realised decades later by the current SuperNova Early Warning System, SNEWS. Together with his co-author Dmitry Nadyozhin, he showed that neutrinos released in star collapses are drivers in the formation of isotopes such as Li-7, Be-8 and B-11 in the supernova shell, and that these processes play an important role in cosmic nucleosynthesis.

In 1980 Domogatsky obtained his doctor of science (equivalent to the Western habilitation) and in the same year became the head of the newly founded Laboratory of Neutrino Astrophysics at High Energies at the Institute for Nuclear Research of the Russian Academy of Sciences, INR RAS. The central goal of this laboratory was, and is, the construction of an underwater neutrino telescope in Lake Baikal, a task to which he devoted all his life from that point on. He created a team of enthusiastic young experimentalists, starting site explorations in the following year and obtaining first physics results with test configurations later in the 1980s. At the end of the 1980s, the plan for a neutrino telescope comprising about 200 photomultipliers (NT200) was born, and realised together with German collaborators in the 1990s. The economic crisis following the breakdown of the Soviet Union would surely have ended the project if not for Domogatsky’s unshakable will and strong leadership. With the partial configuration of the project deployed in 1994, first neutrino candidates were identified in 1996: the proof of concept for underwater neutrino telescopes had been delivered.

He shaped the image of the INR RAS and the field of neutrino astronomy

NT200 was shut down a decade ago, by which time a new cubic-kilometre telescope in Lake Baikal was already under construction. This project was christened Baikal–GVD, with GVD standing for gigaton volume telescope, though these letters could equally well denote Domogatsky’s initials. Thus far it has reached about half of the size of the IceCube neutrino telescope at the South Pole.

Domogatsky was born to a family of artists and was surrounded by an artistic atmosphere whilst growing up. His grandfather was a famous sculptor, his father a painter, woodcrafter and book illustrator. His brother followed in his father’s footsteps, while Grigory himself married Svetlana, an art historian. He possessed an outstanding literary, historical and artistic education, and all who met him were struck by his knowledge, his old-fashioned noblesse and his intellectual charm.

Domogatsky was a corresponding member of the Russian Academy of Sciences and the recipient of many prestigious awards, most notably the Bruno Pontecorvo Prize and the Pavel Cherenkov Prize. With his leadership in the Baikal project, Grigory Domogatsky shaped the scientific image of the INR RAS and the field of neutrino astronomy. He will be remembered as a carefully weighing scientist, as a person of incredible stamina, and as the unforgettable father figure of the Baikal project.

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Elena Accomando, a distinguished collider phenomenologist, passed away on 7 January 2025.

Elena received her laurea in physics from the Sapienza University of Rome in 1993, followed by a PhD from the University of Torino in 1997. Her early career included postdoctoral positions at Texas A&M University and the Paul Scherrer Institute, as well as a staff position at the University of Torino. In 2009 she joined the University of Southampton as a lecturer, earning promotions to associate professor in 2018 and professor in 2022.

Elena’s research focused on the theory and phenomenology of particle physics at colliders, searching for new forces and exotic supersymmetric particles at the Large Hadron Collider. She explored a wide range of Beyond the Standard Model (BSM) scenarios at current and future colliders. Her work included studies of new gauge bosons such as the Z′, extra-dimensional models, and CP-violating effects in BSM frameworks, as well as dark-matter scattering on nuclei and quantum corrections to vector-boson scattering. She was also one of the authors of “WPHACT”, a Monte Carlo event generator developed for four-fermion physics at electron–positron colliders, which remains a valuable tool for precision studies. Elena investigated novel signatures in decays of the Higgs boson, aiming to uncover deviations from Standard Model expectations, and was known for connecting theory with experimental applications, proposing phenomenological strategies that were both realistic and impactful. She was well known as a research collaborator at CERN and other international institutions.

She authored the WPHACT Monte Carlo event generator that remains a valuable tool for precision studies

Elena played an integral role in shaping the academic community at Southampton and was greatly admired as a teacher. Her remarkable professional achievements were paralleled by strength and optimism in the face of adversity. Despite her long illness, she remained a positive presence, planning ahead for her work and her family. Her colleagues and students remember her as a brilliant scientist, an inspiring mentor and a warm and compassionate person. She will also be missed by her longstanding colleagues from the CMS collaboration at Rutherford Appleton Laboratory.

Elena is survived by her devoted husband, Francesco, and their two daughters.

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Shoroku Ohnuma, who made significant contributions to accelerator physics in the US and Japan, passed away on 4 February 2024, at the age of 95.

Born on 19 April 1928, in Akita Prefecture, Japan, Ohnuma graduated from the University of Tokyo’s Physics Department in 1950. After studying with Yoichiro Nambu at Osaka University, he came to the US as a Fulbright scholar in 1953, obtaining his doctorate from the University of Rochester in 1956. He maintained a lifelong friendship with neutrino astrophysicist Masatoshi Koshiba, who received his degree from Rochester in the same period. A photo published in the Japanese national newspaper Asahi Shimbun shows him with Koshiba, Richard Feynman and Nambu when the latter won the Nobel Prize in Physics – Ohnuma would often joke that he was the only one pictured who did not win a Nobel.

Ohnuma spent three years doing research at Yale University before returning to Japan to teach at Waseda University. In 1962 he returned to the US with his wife and infant daughter Keiko to work on linear accelerators at Yale. In 1970 he joined the Fermi National Accelerator Laboratory (FNAL), where he contributed significantly to the completion of the Tevatron before moving to the University of Houston in 1986, where he worked on the Superconducting Super Collider (SSC). While he claimed to have moved to Texas because his work at FNAL was done, he must have had high hopes for the SSC, which the first Bush administration slated to be built in Dallas in 1989. Young researchers who worked with him, including me, made up an energetic but inexperienced working team of accelerator researchers. With many FNAL-linked people such as Helen Edwards in the leadership of SSC, we frequently invited professor Ohnuma to Dallas to review the overall design. He was a mentor to me for more than 35 years after our work together at the Texas Accelerator Center in 1988.

Ohnuma reviewed accelerator designs and educated students and young researchers in the US and Japan

After Congress cancelled the SSC in 1993, Ohnuma continued his research at the University of Houston until 1999. Starting in the late 1990s, he visited the JHF, later J-PARC, accelerator group led by Yoshiharu Mori at the University of Tokyo’s Institute for Nuclear Study almost every year. As a member of JHF’s first International Advisory Committee, he reviewed the accelerator design and educated students and young researchers, whom he considered his grandchildren. Indeed, his guidance had grown gentler and more grandfatherly.

In 2000, in semi-retirement, Ohnuma settled at the University of Hawaii, where he continued to frequent the campus most weekdays until his death. Even after the loss of his wife in 2021, he continued walking every day, taking a bus to the university, doing volunteer work at a senior facility, and visiting the Buddhist temple every Sunday. His interest in Zen Buddhism had grown after retirement, and he resolved to copy the Heart Sutra a thousand times on rice paper, with the sumi brush and ink prepared from scratch. We were entertained by his panic at having nearly achieved his goal too soon before his death. The Heart Sutra is a foundational text in Zen Buddhism, chanted on every formal occasion. Undertaking to copy it 1000 times exemplified his considerable tenacity and dedication. Whatever he undertook in the way of study, he was unhurried and unworried, optimistic and cheerful, and persistent.

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“Confucius famously may or may not have said: ‘When I hear, I forget. When I see, I remember. When I do, I understand.’ And computer-game mechanics can be inspired directly by science. Study it well, and you can invent game mechanics that allow you to engage with and learn about your own reality in a way you can’t when simply watching films or reading books.”

So says Raphael Granier de Cassagnac, a research director at France’s CNRS and Ecole Polytechnique, as well as member of the CMS collaboration at the CMS. Granier de Cassagnac is also the creative director of Exographer, a science-fiction computer game that draws on concepts from particle physics and is available on Steam, Switch, PlayStation 5 and Xbox.

“To some extent, it’s not too different from working at a place like CMS, which is also a super complicated object,” explains Granier de Cassagnac. Developing a game often requires graphic artists, sound designers, programmers and science advisors. To keep a detector like CMS running, you need engineers, computer scientists, accelerator physicists and funding agencies. And that’s to name just a few. Even if you are not the primary game designer or principal investigator, understanding the
fundamentals is crucial to keep the project running efficiently.

Root skills

Most physicists already have some familiarity with structured programming and data handling, which eases the transition into game development. Just as tools like ROOT and Geant4 serve as libraries for analysing particle collisions, game engines such as Unreal, Unity or Godot provide a foundation for building games. Prebuilt functionalities are used to refine the game mechanics.

“Physicists are trained to have an analytical mind, which helps when it comes to organising a game’s software,” explains Granier de Cassagnac. “The engine is merely one big library, and you never have to code anything super complicated, you just need to know how to use the building blocks you have and code in smaller sections to optimise the engine itself.”

While coding is an essential skill for game production, it is not enough to create a compelling game. Game design demands storytelling, character development and world-building. Structure, coherence and the ability to guide an audience through complex information are also required.

“Some games are character-driven, others focus more on the adventure or world-building,” says Granier de Cassagnac. “I’ve always enjoyed reading science fiction and playing role-playing games like Dungeons and Dragons, so writing for me came naturally.”

Entrepreneurship and collaboration are also key skills, as it is increasingly rare for developers to create games independently. Universities and startup incubators can provide valuable support through funding and mentorship. Incubators can help connect entrepreneurs with industry experts, and bridge the gap between scientific research and commercial viability.

“Managing a creative studio and a company, as well as selling the game, was entirely new for me,” recalls Granier de Cassagnac. “While working at CMS, we always had long deadlines and low pressure. Physicists are usually not prepared for the speed of the industry at all. Specialised offices in most universities can help with valorisation – taking scientific research and putting it on the market. You cannot forget that your academic institutions are still part of your support network.”

Though challenging to break into, opportunity abounds for those willing to upskill

The industry is fiercely competitive, with more games being released than players can consume, but a well-crafted game with a unique vision can still break through. A common mistake made by first-time developers is releasing their game too early. No matter how innovative the concept or engaging the mechanics, a game riddled with bugs frustrates players and damages its reputation. Even with strong marketing, a rushed release can lead to negative reviews and refunds – sometimes sinking a project entirely.

“In this industry, time is money and money is time,” explains Granier de Cassagnac. But though challenging to break into, opportunity abounds for those willing to upskill, with the gaming industry worth almost $200 billion a year and reaching more than three billion players worldwide by Granier de Cassagnac’s estimation. The most important aspects for making a successful game are originality, creativity, marketing and knowing the engine, he says.

“Learning must always be part of the process; without it we cannot improve,” adds Granier de Cassagnac, referring to his own upskilling for the company’s next project, which will be even more ambitious in its scientific coverage. “In the next game we want to explore the world as we know it, from the Big Bang to the rise of technology. We want to tell the story of humankind.”

The post Game on for physicists appeared first on CERN Courier.

A theory of massive gravity is one in which the graviton, the particle that is believed to mediate the force of gravity, has a small mass. This contrasts with general relativity, our current best theory of gravity, which predicts that the graviton is exactly massless. In 2011, Claudia de Rham (Imperial College London), Gregory Gabadadze (New York University) and Andrew Tolley (Imperial College London) revitalised interest in massive gravity by uncovering the structure of the best possible (in a technical sense) theory of massive gravity, now known as the dRGT theory, after these authors.

Claudia de Rham has now written a popular book on the physics of gravity. The Beauty of Falling is an enjoyable and relatively quick read: a first-hand and personal glimpse into the life of a theoretical physicist and the process of discovery.

De Rahm begins by setting the stage with the breakthroughs that led to our current paradigm of gravity. The Michelson–Morley experiment and special relativity, Einstein’s description of gravity as geometry leading to general relativity and its early experimental triumphs, black holes and cosmology are all described in accessible terms using familiar analogies. De Rham grips the reader by weaving in a deeply personal account of her own life and upbringing, illustrating what inspired her to study these ideas and pursue a career in theoretical physics. She has led an interesting life, from growing up in various parts of the world, to learning to dive and fly, to training as an astronaut and coming within a hair’s breadth of becoming one. Her account of the training and selection process for European Space Agency astronauts is fascinating, and worth the read in its own right.

Moving closer to the present day, de Rahm discusses the detection of gravitational waves at gravitational-wave observatories such as LIGO, the direct imaging of black holes by the Event Horizon Telescope, and the evidence for dark matter and the accelerating expansion of the universe with its concomitant cosmological constant problem. As de Rham explains, this latter discovery underlies much of the interest in massive gravity; there remains the lingering possibility that general relativity may need to be modified to account for the observed accelerated expansion.

In the second part of the book, de Rham warns us that we are departing from the realm of well tested and established physics, and entering the world of more uncertain ideas. A pet peeve of mine is popular accounts that fail to clearly make this distinction, a temptation to which this book does not succumb. 

Here, the book offers something that is hard to find: a first-hand account of the process of thought and discovery in theoretical physics. When reading the latest outrageously overhyped clickbait headlines coming out of the world of fundamental physics, it is easy to get the wrong impression about what theoretical physicists do. This part of the book illustrates how ideas come about: by asking questions of established theories and tugging on their loose threads, we uncover new mathematical structures and, in the process, gain a deeper understanding of the structures we have.

Massive gravity, the focus of this part of the book, is a prime example: by starting with a basic question, “does the graviton have to be massless?”, a new structure was revealed. This structure may or may not have any direct relevance to gravity in the real world, but even if it does not, our study of it has significantly enhanced our understanding of the structure of general relativity. And, as has occurred countless times before with intriguing mathematical structures, it may ultimately prove useful for something completely different and unforeseen – something that its originators did not have even remotely in mind. Here, de Rahm offers invaluable insights both into uncovering a new theoretical structure and what happens next, as the results are challenged and built upon by others in the community.

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Guido Barbiellini Amidei, who passed away on 15 November 2024, made fundamental contributions to both particle physics and astrophysics.

In 1959 Guido earned a degree in physics from Rome University with a thesis on electron bremsstrahlung in monocrystals under Giordano Diambrini, a skilled experimentalist and excellent teacher. Another key mentor was Marcello Conversi, spokesperson for one of the detectors at the Adone electron–positron collider at INFN Frascati, where Guido became a staff member and developed the first luminometer based on small-angle electron–positron scattering – a technique still used today. Together with Shuji Orito, he also built the first double-tagging system for studying gamma-ray collisions.

Guido later spent several years at CERN, collaborating with Carlo Rubbia, first on the study of K-meson decays at the Proton Synchrotron and then on small-angle proton–proton scattering at the Intersecting Storage Rings. In 1974 he proposed an experiment in a new field for him: neutrino-electron scattering, a fundamental but extremely rare phenomenon known from a handful of events seen in Gargamelle. To distinguish electromagnetic showers from hadronic ones, the CHARM collaboration built a “light” calorimeter made of 150 tonnes of Carrara marble. From 1979 to 1983, 200 electron–neutrino scattering events were recorded.

In 1980 Guido remarked to his friend Ugo Amaldi: “Why don’t we start our own collaboration for LEP instead of joining others?” This suggestion sparked the genesis of the DELPHI collaboration, in which Guido played a pivotal role in defining its scientific objectives and overseeing the construction of the barrel electromagnetic calorimeter. He also contributed significantly to the design of the luminosity monitors. Above all, Guido was a constant driving force within the experiment, offering innovative ideas for fundamental physics during the transition to LEP’s higher-energy phase, and engaging tirelessly with both young students and senior colleagues.

Guido’s insatiable scientific curiosity also extended to CP symmetry violation. In 1989 he co-organised a workshop, with Konrad Kleinknecht and Walter Hoogland, exploring the possibility of an electron–positron ϕ-factory to study CP violation in neutral kaon decays. Two of his papers, with Claudio Santoni, laid the groundwork for constructing the DAΦNE collider in Frascati.

The year 1987 was a turning point for Guido. Firstly, he became a professor at the University of Trieste. Secondly, the detection of neutrinos produced by Supernova 1987A inspired a letter, published in Nature in collaboration with Giuseppe Cocconi, in which it was established that neutrinos have a charge smaller than 10^–17 elementary charges. Thirdly, Guido presented a new idea to mount silicon detectors (which he had encountered through work done in DELPHI by Bernard Hyams and Peter Weilhammer) on the International Space Station or a spacecraft to detect cosmic rays and their showers, which led to a seminal paper.

At the beginning of the 1990s, an international collaboration for a large NASA space mission focused on gamma-ray astrophysics (initially named GLAST) began to form, led by SLAC scientists. Guido was among the first proponents and later was the national representative of many INFN groups. The mission, later renamed Fermi, was launched in 2008 and continues to produce significant insights in topics ranging from neutron stars and black holes to dark-matter annihilation.

Beyond GLAST, Guido was captivated by the application of silicon sensors to a new programme of small space missions initiated by the Italian Space Agency. The AGILE gamma-ray astrophysics mission, for which Guido was co-principal investigator, was conceived and approved during this period. Launched in 2007, AGILE made numerous discoveries over nearly 17 years, including identifying the origin of hadronic cosmic rays in supernova remnants and discovering novel, rapid particle acceleration phenomena in the Crab Nebula.

Guido’s passion for physics made him inexhaustible. He always brought fresh insights and thoughtful judgments, fostering a collaborative environment that enriched all the projects he took part in. He was not only a brilliant physicist but also a true gentleman of calm and mild manners, widely appreciated as a teacher and as director of INFN Trieste. Intellectually free and always smiling, he conveyed determination and commitment with grace and a profound dedication to nurturing young talents. He will be deeply missed.

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Meinhard Regler, an expert in detector development and software analysis, passed away on 22 September 2024 at the age of 83.

Born and raised in Vienna, Meinhard studied physics at the Technical University Vienna (TUW) and completed his master’s thesis on deuteron acceleration in a linac at CERN. In 1966 he joined the newly founded Institute of High Energy Physics (HEPHY) of the Austrian Academy of Sciences. He settled in Geneva to participate in a counter experiment at the CERN Proton Synchrotron, and in 1970 obtained his PhD with distinction from TUW.

In 1970 Meinhard became staff member in CERN’s data-handling division. He joined the Split Field Magnet experiment at the Intersecting Storage Rings and, together with HEPHY, contributed specially designed multi-wire proportional chambers. Early on, he realised the importance of rigorous statistical methods for track and vertex reconstruction in complex detectors, resulting in several seminal papers.

In 1975 Meinhard returned to Vienna as leader of HEPHY’s experimental division. From 1993 until his retirement at the end of 2006 he was deputy director and responsible for the detector development and software analysis groups. As a faculty member of TUW he created a series of specialised lectures and practical courses, which shaped a generation of particle physicists. In 1978 Meinhard and Georges Charpak founded the Wire Chamber Conference, now known as the Vienna Conference on Instrumentation (VCI).

Meinhard continued his participation in experiments at CERN, including WA6, UA1 and the European Hybrid Spectrometer. After joining the DELPHI experiment at LEP, he realised the emerging potential of semiconductor tracking devices and established this technology at HEPHY. First applied at DELPHI’s Very Forward Tracker, this expertise was successfully continued with important contributions to the CMS tracker at LHC, the Belle vertex detector at KEKB and several others.

Meinhard is author and co-author of several hundred scientific papers. His and his group’s contributions to track and vertex reconstruction are summarised in the standard textbook Data Analysis Techniques for High-Energy Physics, published by Cambridge University Press and translated into Russian and Chinese.

All that would suffice for a lifetime achievement, but not so for Meinhard. Inspired by the fall of the Iron Curtain, he envisaged the creation of an international centre of excellence in the Vienna region. Initially planned as a spallation neutron source, the project eventually transmuted into a facility for cancer therapy by proton and carbon-ion beams, called MedAustron. Financed by the province of Lower Austria and the hosting city of Wiener Neustadt, and with crucial scientific and engineering support from CERN and Austrian institutes, clinical treatment started in 2016.

Meinhard received several prizes and was rewarded with the highest scientific decoration of Austria

Meinhard was invited as a lecturer to many international conferences and post-graduate schools worldwide. He chaired the VCI series, organised several accelerator schools and conferences in Austria, and served on the boards of the European Physical Society’s international group on accelerators. For his tireless scientific efforts and in particular the realisation of MedAustron, Meinhard received several prizes and was rewarded with the highest scientific decoration of Austria – the Honorary Cross for Science and Arts of First Class.

He was also a co-founder and long-term president of a non-profit organisation in support of mentally handicapped people. His character was incorruptible, strictly committed to truth and honesty, and responsive to loyalty, independent thinking and constructive criticism.

In Meinhard Regler we have lost an enthusiastic scientist, visionary innovator, talented organiser, gifted teacher, great humanist and good friend. His legacy will forever stay with us.

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In a paper published in 1969, Khriplovich was the first to discover the phenomenon of anti-screening in the SU(2) Yang–Mills theory by calculating the first loop correction to the charge renormalisation. This immediately translates into the crucial first coefficient (–22/3) of the Gell-Mann–Low function and asymptotic freedom of the theory.

Regretfully, Khriplovich did not follow this interpretation of his result even after the key SLAC experiment on deep inelastic scattering and its subsequent partonic interpretation by Feynman. The honour of the discovery of asymptotic freedom in QCD went to three authors of papers published in 1973, who seemingly did not know of Khriplo­vich’s calculations.

In the early 1970s, Khriplovich’s interests turned to fundamental questions on the way towards the Standard Model. One was whether the electroweak theory is described by the Weinberg–Salam model, with neutral currents interacting via Z bosons, or the Georgi–Glashow model without them. While neutrino scattering on nucleons was soon confirmed, the electron interaction with nucleons was still unchecked. One practical way to find out was to use atomic spectroscopy to look for any mixing between states of opposite parity. Actively entering this area, Khriplovich and his students worked out quantitative predictions for the rotation of laser polarisation due to the weak interaction between electrons and nucleons. Their predictions were triumphantly confirmed in experiments, firstly by Barkov and Zolotorev at the Budker Institute. The same parity violating interaction was later observed at SLAC in 1978, proving the Z-exchange and the Weinberg–Salam model beyond any doubt. In 1973, together with Arkady Vainshtein, Khriplovich also derived the first solid limit on the mass of the charm quark that was unexpectedly discovered the following year.

He became engaged in Yang–Mills theories at a time when very few people were interested in them

The work of Khriplovich and his group significantly advanced the theory of many-electron atoms and contributed to the subsequent studies of the violation of fundamental symmetries in processes involving elementary particles, atoms, molecules and atomic nuclei. His students and later close collaborators, such as Victor Flambaum, Oleg Sushkov and Maxim Pospelov, grew as strong physicists who made important contributions to various subfields of theoretical physics. He was awarded the Silver Dirac Medal by the University of New South Wales (Sydney) and the Pomeranchuk Prize by the Institute of Theoretical and Experimental Physics (Moscow).

Yulik, as he was affectionately known, had his own style in physics. He was feisty and focused on issues where he could become a trailblazer, unafraid to cut relations with scientists of any rank if he felt their behaviour did not match his high ethical standards. This is why he became engaged in Yang–Mills theories at a time when very few people were interested in them. Yet, Yulik was always graceful and respectful in his interactions with others, and smiling, as we would like to remember him.

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Karel graduated in theoretical physics in Bratislava, Slovakia (then Czechoslovakia) in 1976 and worked at JINR Dubna for over 10 years, participating in experiments in Serpukhov and doing theoretical studies on the phenomenology of particle production at high energies. In 1990 he joined Collège de France and the heavy-ion programme at CERN, soon becoming one of the most influential scientists in the Omega series of heavy-ion experiments (WA85, WA94, WA97, NA57) at the CERN Super Proton Synchrotron (SPS). In 2002 Karel was awarded the Slovak Academy of Sciences Prize for his contributions to the observation of the enhancement of the production of multi-strange particles in heavy-ion collisions at the SPS. In 2013 he was awarded the medal of the Czech Physical Society.

As early as 1991, Karel was part of the small group who designed the first heavy-ion detector for the LHC, which later became ALICE. He played a central role in shaping the ALICE experiment, from the definition of physics topics and the detector layout to the design of the data format, tracking, data storage and data analysis. He was pivotal in convincing the collaboration to introduce two layers of pixel detectors to reconstruct decays of charm hadrons only a few tens of microns from the primary vertex in central lead–lead collisions at the LHC – an idea considered by many to be impossible in heavy-ion collisions, but that is now one of the pillars of the ALICE physics programme. He was the ALICE physics coordinator for many years leading up to and including first data taking. Over the years, he also made multiple contributions to ALICE upgrade studies and became known as the “wise man” to be consulted on the trickiest questions.

Karel was a top-class physicist, with a sharp analytical mind, a legendary memory, a seemingly unlimited set of competences ranging from higher mathematics to formal theory, and from detector physics to high-performance computing. At the same time he was a generous, caring and kind colleague who supported, helped, mentored and guided a large number of ALICE collaborators. We miss him dearly.

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Günter Wolf, who played a leading role in the planning, construction and data analysis of experiments that were instrumental in establishing the Standard Model, passed away on 29 October 2024 at the age of 86. He significantly shaped and contributed to the research programme of DESY, and knew better than almost anyone how to form international collaborations and lead them to the highest achievements.

Born in Ulm, Germany in 1937, Wolf studied physics in Tübingen. At the urging of his supervisor Helmut Faissner, he went to Hamburg in 1961 where the DESY synchrotron was being built under DESY founder Willibald Jentschke. Together with Erich Lohrmann and Martin Teucher, he was involved in the preparation of the bubble-chamber experiments there and at the same time took part in experiments at CERN.

The first phase of experiments with high-energy photons at the DESY synchrotron, in which he was involved, had produced widely recognised results on the electromagnetic interactions of elementary particles. In 1967 Wolf seized the opportunity to continue this research at the higher energies of the recently completed linear accelerator at Stanford University (SLAC). He became the spokesperson for an experiment with a polarised gamma beam, which provided new insights into the nature of vector mesons.

In 1971, Jentschke succeeded in bringing Wolf back to Hamburg as senior scientist. He remained associated with DESY for the rest of his life and became a leader in the planning, construction and analysis of key DESY experiments.

Together with Bjørn Wiik, as part of an international collaboration, Wolf designed and realised the DASP detector for DORIS, the first electron–positron storage ring at DESY. This led to the discovery of the excited states of charmonium in 1975 and thus to the ultimate confirmation that quarks are particles. For the next, larger electron–positron storage ring, PETRA, he designed the TASSO detector, again together with Wiik. In 1979, the TASSO collaboration was able to announce the discovery of the gluon through its spokesperson Wolf, for which he, together with colleagues from TASSO, was awarded the High Energy Particle Physics Prize of the European Physical Society.

Wolf’s negotiating skills and deep understanding of physics and technology served particle physics worldwide

In 1982 Wolf became the chair of the experiment selection committee for the planned LEP collider at CERN. His deep understanding of physics and technology, and his negotiating skills, were an essential foundation for the successful LEP programme, just one example of how Wolf has served particle physics worldwide as a member of international scientific committees.

At the same time, Wolf was involved in the planning of the physics programme for the electron–proton collider HERA. The ZEUS general-purpose detector for experiments at HERA was the work of an international collaboration of more than 400 scientists, that Wolf brought together and led as its spokesperson for many years. The experiments at HERA ran from 1992 to 2007, producing outstanding results that include the direct demonstration of the unification of the weak and electromagnetic force at high momentum transfers, the precise measurement of the structure of the proton, which is determined by quarks and gluons, and the surprising finding that there are collisions in which the proton remains intact even at the highest momentum transfers. In 2011 Wolf was awarded the Stern–Gerlach Medal of the German Physical Society, its highest award for achievements in experimental physics.

When dealing with colleagues and staff, Günter Wolf was always friendly, helpful, encouraging and inspiring, but at the same time demanding and insistent on precision and scientific excellence. He took the opinions of others seriously, but only a thorough and competent analysis could convince him. As a result, he enjoyed the greatest respect from everyone and became a role model and friend to many. DESY owes its reputation in the international physics community not least to people like him.

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Should we start with your father’s involvement in the founding of CERN?

I began hearing my father talk about a new European laboratory while I was still in high school in Rome. Our lunch table was always alive with discussions about science, physics and the vision of this new laboratory. Later, I learned that between 1948 and 1949, my father was deeply engaged in these conversations with two of his friends: Gilberto Bernardini, a well-known cosmic-ray expert, and Bruno Ferretti, a professor of theoretical physics at Rome University. I was 15 years old and those table discussions remain vivid in my memory.

So, the idea of a European laboratory was already being discussed before the 1950 UNESCO meeting?

Yes, indeed. Several eminent European physicists, including my father, Pierre Auger, Lew Kowarski and Francis Perrin, recognised that Europe could only be competitive in nuclear physics through collaborative efforts. All the actors wanted to create a research centre that would stop the post-war exodus of physics talent to North America and help rebuild European science. I now know that my father’s involvement began in 1946 when he travelled to Cambridge, Massachusetts, for a conference. There, he met Nobel Prize winner John Cockcroft, and their conversations planted in his mind the first seeds for a European laboratory.

Parallel to scientific discussions, there was an important political initiative led by Swiss philosopher and writer Denis de Rougemont. After spending the war years at Princeton University, he returned to Europe with a vision of fostering unity and peace. He established the Institute of European Culture in Lausanne, Switzerland, where politicians from France, Britain and Germany would meet. In December 1949, during the European Cultural Conference in Lausanne, French Nobel Prize winner Louis de Broglie sent a letter advocating for a European laboratory where scientists from across the continent could work together peacefully.

My father strongly believed in the importance of accelerators to advance the new field that, at the time, was at the crossroads between nuclear physics and cosmic-ray physics. Before the war, in 1936, he had travelled to Berkeley to learn about cyclotrons from Ernest Lawrence. He even attempted to build a cyclotron in Italy in 1942, profiting from the World’s Fair that had to be held in Rome. Moreover, he was deeply affected by the exodus of talented Italian physicists after the war, including Bruno Rossi, Gian Carlo Wick and Giuseppe Cocconi. He saw CERN as a way to bring these scientists back and rebuild European physics.

How did Isidor Rabi’s involvement come into play?

In 1950 my father was corresponding with Gilberto Bernardini, who was spending a year at Columbia University. There Bernardini mentioned the idea of a European laboratory to Isidor Rabi, who, at the same time, was in contact with other prominent figures in this decentralised and multi-centered initiative. Together with Norman Ramsay, Rabi had previously succeeded, in 1947, in persuading nine northeastern US universities to collaborate under the banner of Associated Universities, Inc, which led to the establishment of Brookhaven National Laboratory.

What is not generally known is that before Rabi gave his famous speech at the fifth assembly of UNESCO in Florence in June 1950, he came to Rome and met with my father. They discussed how to bring this idea to fruition. A few days later, Rabi’s resolution at the UNESCO meeting calling for regional research facilities was a crucial step in launching the project. Rabi considered CERN a peaceful compensation for the fact that physicists had built the nuclear bomb.

How did your father and his colleagues proceed after the UNESCO resolution?

Following the UNESCO meeting, Pierre Auger, at that time director of exact and natural sciences at UNESCO, and my father took on the task of advancing the project. In September 1950 Auger spoke of it at a nuclear physics conference in Oxford, and at a meeting of the International Union of Pure and Applied Physics (IUPAP), my father– one of the vice presidents – urged the executive committee to consider how best to implement the Florence resolution. In May 1951, Auger and my father organised a meeting of experts at UNESCO headquarters in Paris, where a compelling justification for the European project was drafted.

The cost of such an endeavour was beyond the means of any single nation. This led to an intergovernmental conference under the auspices of UNESCO in December 1951, where the foundations for CERN were laid. Funding, totalling $10,000 for the initial meetings of the board of experts, came from Italy, France and Belgium. This was thanks to the financial support of men like Gustavo Colonnetti, president of the Italian Research Council, who had already – a year before – donated the first funds to UNESCO.

Were there any significant challenges during this period?

Not everyone readily accepted the idea of a European laboratory. Eminent physicists like Niels Bohr, James Chadwick and Hendrik Kramers questioned the practicality of starting a new laboratory from scratch. They were concerned about the feasibility and allocation of resources, and preferred the coordination of many national laboratories and institutions. Through skilful negotiation and compromise, Auger and my father incorporated some of the concerns raised by the sceptics into a modified version of the project, ensuring broader support. In February 1952 the first agreement setting up a provisional council for CERN was written and signed, and my father was nominated secretary general of the provisional CERN.

He worked tirelessly, travelling through Europe to unite the member states and start the laboratory’s construction. In particular, the UK was reluctant to participate fully. They had their own advanced facilities, like the 40 MeV cyclotron at the University of Liverpool. In December 1952 my father visited John Cockcroft, at the time director of the Harwell Atomic Energy Research Establishment, to discuss this. There’s an interesting episode where my father, with Cockcroft, met Frederick Lindemann and Baron Cherwell, who was a long-time scientific advisor to Winston Churchill. Cherwell dismissed CERN as another “European paper mill.” My father, usually composed, lost his temper and passionately defended the project. During the following visit to Harwell, Cockcroft reassured him that his reaction was appropriate. From that point on, the UK contributed to CERN, albeit initially as a series of donations rather than as the result of a formal commitment. It may be interesting to add that, during the same visit to London and Harwell, my father met the young John Adams and was so impressed that he immediately offered him a position at CERN.

What were the steps following the ratification of CERN’s convention?

Robert Valeur, chairman of the council during the interim period, and Ben Lockspeiser, chairman of the interim finance committee, used their authority to stir up early initiatives and create an atmosphere of confidence that attracted scientists from all over Europe. As Lew Kowarski noted, there was a sense of “moral commitment” to leave secure positions at home and embark on this new scientific endeavour.

During the interim period from May 1952 to September 1954, the council convened three sessions in Geneva whose primary focus was financial management. The organisation began with an initial endowment of approximately 1 million Swiss Francs, which – as I said – included a contribution from the UK known as the “observer’s gift”. At each subsequent session, the council increased its funding, reaching around 3.7 million Swiss Francs by the end of this period. When the permanent organisation was established, an initial sum of 4.1 million Swiss Francs was made available.

In 1954, my father was worried that if the parliaments didn’t approve the convention before winter, then construction would be delayed because of the wintertime. So he took a bold step and, with the approval of the council president, authorised the start of construction on the main site before the convention was fully ratified.

This led to Lockspeiser jokingly remarking later that council “has now to keep Amaldi out of jail”. The provisional council, set up in 1952, was dissolved when the European Organization for Nuclear Research officially came into being in 1954, though the acronym CERN (Conseil Européen pour la Recherche Nucléaire) was retained. By the conclusion of the interim period, CERN had grown significantly. A critical moment occurred on 29 September  1954, when a specific point in the ratification procedure was reached, rendering all assets temporarily ownerless. During this eight-day period, my father, serving as secretary general, was the sole owner on behalf of the newly forming permanent organisation. The interim phase concluded with the first meeting of the permanent council, marking the end of CERN’s formative years.

Did your father ever consider becoming CERN’s Director-General?

People asked him to be Director-General, but he declined for two reasons. First, he wanted to return to his students and his cosmic-ray research in Rome. Second, he didn’t want people to think he had done all this to secure a prominent position. He believed in the project for its own sake.

When the convention was finally ratified in 1954, the council offered the position of Director-General to Felix Bloch, a Swiss–American physicist and Nobel Prize winner for his work on nuclear magnetic resonance. Bloch accepted but insisted that my father serve as his deputy. My father, dedicated to CERN’s success, agreed to this despite his desire to return to Rome full time.

How did that arrangement work out?

My father agreed but Bloch wasn’t at that time rooted in Europe. He insisted on bringing all his instruments from Stanford so he could continue his research on nuclear magnetic resonance at CERN. He found it difficult to adapt to the demands of leading CERN and soon resigned. The council then elected Cornelis Jan Bakker, a Dutch physicist who had led the synchrocyclotron group, as the new Director-General. From the beginning, he was the person my father thought would have been the ideal director for the initial phase of CERN. Tragically though, Bakker died in a plane crash a year and a half later. I well remember how hard my father was hit by this loss.

How did the development of accelerators at CERN progress?

The decision to adopt the strong focusing principle for the Proton Synchrotron (PS) was a pivotal moment. In August 1952 Otto Dahl, leader of the Proton Synchrotron study group, Frank Goward and Rolf Widerøe visited Brookhaven just as Ernest Courant, Stanley Livingston and Hartland Snyder were developing this new principle. They were so excited by this development that they returned to CERN determined to incorporate it into the PS design. In 1953 Mervyn Hine, a long-time friend of John Adams with whom he had moved to CERN, studied potential issues with misalignment in strong focusing magnets, which led to further refinements in the design. Ultimately, the PS became operational before the comparable accelerator at Brookhaven, marking a significant achievement for European science.

It’s important here to recognise the crucial contributions of the engineers, who often don’t receive the same level of recognition as physicists. They are the ones who make the work of experimental physicists and theorists possible. “Viki” Weisskopf, Director-General of CERN from 1961 to 1965, compared the situation to the discovery of America. The machine builders are the captains and shipbuilders. The experimentalists are those fellows on the ships who sailed to the other side of the world and wrote down what they saw. The theoretical physicists are those who stayed behind in Madrid and told Columbus that he was going to land in India.

Your father also had a profound impact on the development of other Big Science organisations in Europe

Yes, in 1958 my father was instrumental, together with Pierre Auger, in the founding of the European Space Agency. In a letter written in 1958 to his friend Luigi Crocco, who was professor of jet propulsion in Princeton, he wrote that “it is now very much evident that this problem is not at the level of the single states like Italy, but mainly at the continental level. Therefore, if such an endeavour is to be pursued, it must be done on a European scale, as already done for the building of the large accelerators for which CERN was created… I think it is absolutely imperative for the future organisation to be neither military nor linked to any military organisation. It must be a purely scientific organisation, open – like CERN – to all forms of cooperation and outside the participating countries.” This document reflects my father’s vision of peaceful and non-military European science.

How is it possible for one person to contribute so profoundly to science and global collaboration?

My father’s ability to accept defeats and keep pushing forward was key to his success. He was an exceptional person with a clear vision and unwavering dedication. I hope that by sharing these stories, others might be inspired to pursue their goals with the same persistence and passion.

Could we argue that he was not only a visionary but also a relentless advocate?

He travelled extensively, talked to countless people, and was always cheerful and energetic. He accepted setbacks but kept moving forwards. In this connection, I want to mention Eliane Bertrand, later de Modzelewska, his secretary in Rome who later became secretary of the CERN Council for about 20 years, serving under several Director-Generals. She left a memoir about those early days, highlighting how my father was always travelling, talking and never stopping. It’s a valuable piece of history that, I think, should be published.

International collaboration has been a recurring theme in your own career. How do you view its importance today?

International collaboration is more critical than ever in today’s world. Science has always been a bridge between cultures and nations, and CERN’s history is a testimony of what this brings to humanity. It transcends political differences and fosters mutual understanding. I hope CERN and the broader scientific community will find ways to maintain these vital connections with all countries. I’ve always believed that fostering a collaborative and inclusive environment is one of the main goals of us scientists. It’s not just about achieving results but also about how we work together and support each other along the way.

Looking ahead, what are your thoughts on the future of CERN and particle physics?

I firmly believe that pursuing higher collision energies is essential. While the Large Hadron Collider has achieved remarkable successes, there’s still much we haven’t uncovered – especially regarding supersymmetry. Even though minimal supersymmetry does not apply, I remain convinced that supersymmetry might manifest in ways we haven’t yet understood. Exploring higher energies could reveal supersymmetric particles or other new phenomena.

Like most European physicists, I support the initiative of the Future Circular Collider and starting with an electron–positron collider phase so to explore new frontiers at two very different energy levels. However, if geopolitical shifts delay or complicate these plans, we should consider pushing hard on alternative strategies like developing the technologies for muon colliders.

Ugo Amaldi first arrived at CERN as a fellow in September 1961. Then, for 10 years at the ISS in Rome, he opened two new lines of research: quasi-free electron scattering on nuclei and atoms. Back at CERN, he developed the Roman pots experimental technique, was a co-discoverer of the rise of the proton–proton cross-section with energy, measured the polarisation of muons produced by neutrinos, proposed the concept of a superconducting electron–positron linear collider, and led LEP’s DELPHI Collaboration. Today, he advances the use of accelerators in cancer treatment as the founder of the TERA Foundation for hadron therapy and as president emeritus of the National Centre for Oncological Hadrontherapy (CNAO) in Pavia. He continues his mother and father’s legacy of authoring high-school physics textbooks used by millions of Italian pupils. His motto is: “Physics is beautiful and useful.”

This interview first appeared in the newsletter of CERN’s experimental physics department. It has been edited for concision.

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What motivates you to be CERN’s next Director-General?

CERN is an incredibly important organisation. I believe my deep passion for particle physics, coupled with the experience I have accumulated in recent years, including leading the Deep Underground Neutrino Experiment, DUNE, through a formative phase, and running the Science and Technology Facilities Council in the UK, has equipped me with the right skill set to lead CERN though a particularly important period.

How would you describe your management style?

That’s a good question. My overarching approach is built around delegating and trusting my team. This has two advantages. First, it builds an empowering culture, which in my experience provides the right environment for people to thrive. Second, it frees me up to focus on strategic planning and engagement with numerous key stakeholders. I like to focus on transparency and openness, to build trust both internally and externally.

How will you spend your familiarisation year before you take over in 2026?

First, by getting a deep understanding of CERN “from within”, to plan how I want to approach my mandate. Second, by lending my voice to the scientific discussion that will underpin the third update to the European strategy for particle physics. The European strategy process is a key opportunity for the particle-physics community to provide genuine bottom-up input and shape the future. This is going to be a really varied and exciting year.

What open question in fundamental physics would you most like to see answered in your lifetime?

I am going to have to pick two. I would really like to understand the nature of dark matter. There are a wide range of possibilities, and we are addressing this question from multiple angles; the search for dark matter is an area where the collider and non-collider experiments can both contribute enormously. The second question is the nature of the Higgs field. The Higgs boson is just so different from anything else we’ve ever seen. It’s not just unique – it’s unique and very strange. There are just so many deep questions, such as whether it is fundamental or composite. I am confident that we will make progress in the coming years. I believe the High-Luminosity LHC will be able to make meaningful measurements of the self-coupling at the heart of the Higgs potential. If you’d asked me five years ago whether this was possible, I would have been doubtful. But today I am very optimistic because of the rapid progress with advanced analysis techniques being developed by the brilliant scientists on the LHC experiments.

What areas of R&D are most in need of innovation to meet our science goals?

Artificial intelligence is changing how we look at data in all areas of science. Particle physics is the ideal testing ground for artificial intelligence, because our data is complex there are none of the issues around the sensitive nature of the data that exist in other fields. Complex multidimensional datasets are where you’ll benefit the most from artificial intelligence. I’m also excited by the emergence of new quantum technologies, which will open up fresh opportunities for our detector systems and also new ways of doing experiments in fundamental physics. We’ve only scratched the surface of what can be achieved with entangled quantum systems.

How about in accelerator R&D?

There are two areas that I would like to highlight: making our current technologies more sustainable, and the development of high-field magnets based on high-temperature superconductivity. This connects to the question of innovation more broadly. To quote one example among many, high-temperature superconducting magnets are likely to be an important component of fusion reactors just as much as particle accelerators, making this a very exciting area where CERN can deploy its engineering expertise and really push that programme forward. That’s not just a benefit for particle physics, but a benefit for wider society.

How has CERN changed since you were a fellow back in 1994?

The biggest change is that the collider experiments are larger and more complex, and the scientific and technical skills required have become more specialised. When I first came to CERN, I worked on the OPAL experiment at LEP – a collaboration of less than 400 people. Everybody knew everybody, and it was relatively easy to understand the science of the whole experiment.

My overarching approach is built around delegating and trusting my team

But I don’t think the scientific culture of CERN and the particle-physics community has changed much. When I visit CERN and meet with the younger scientists, I see the same levels of excitement and enthusiasm. People are driven by the wonderful mission of discovery. When planning the future, we need to ensure that early-career researchers can see a clear way forward with opportunities in all periods of their career. This is essential for the long-term health of particle physics. Today we have an amazing machine that’s running beautifully: the LHC. I also don’t think it is possible to overstate the excitement of the High-Luminosity LHC. So there’s a clear and exciting future out to the early 2040s for today’s early-career researchers. The question is what happens beyond that? This is one reason to ensure that there is not a large gap between the end of the High-Luminosity LHC and the start of whatever comes next.

Should the world be aligning on a single project?

Given the increasing scale of investment, we do have to focus as a global community, but that doesn’t necessarily mean a single project. We saw something similar about 10 years ago when the global neutrino community decided to focus its efforts on two complementary long-baseline projects, DUNE and Hyper-Kamiokande. From the perspective of today’s European strategy, the Future Circular Collider (FCC) is an extremely appealing project that would map out an exciting future for CERN for many decades. I think we’ll see this come through strongly in an open and science-driven European strategy process.

How do you see the scientific case for the FCC?

For me, there are two key points. First, gaining a deep understanding of the Higgs boson is the natural next step in our field. We have discovered something truly unique, and we should now explore its properties to gain deeper insights into fundamental physics. Scientifically, the FCC provides everything you want from a Higgs factory, both in terms of luminosity and the opportunity to support multiple experiments.

Second, investment in the FCC tunnel will provide a route to hadron–hadron collisions at the 100 TeV scale. I find it difficult to foresee a future where we will not want this capability.

These two aspects make the FCC a very attractive proposition.

How successful do you believe particle physics is in communicating science and societal impacts to the public and to policymakers?

I think we communicate science well. After all, we’ve got a great story. People get the idea that we work to understand the universe at its most basic level. It’s a simple and profound message.

Going beyond the science, the way we communicate the wider industrial and societal impact is probably equally important. Here we also have a good story. In our experiments we are always pushing beyond the limits of current technology, doing things that have not been done before. The technologies we develop to do this almost always find their way back into something that will have wider applications. Of course, when we start, we don’t know what the impact will be. That’s the strength and beauty of pushing the boundaries of technology for science.

Would the FCC give a strong return on investment to the member states?

Absolutely. Part of the return is the science, part is the investment in technology, and we should not underestimate the importance of the training opportunities for young people across Europe. CERN provides such an amazing and inspiring environment for young people. The scale of the FCC will provide a huge number of opportunities for young scientists and engineers.

We need to ensure that early-career researchers can see a clear way forward with opportunities in all periods of their career. This is essential for the long-term health of particle physics

In terms of technology development, the detectors for the electron–positron collider will provide an opportunity for pushing forward and deploying new, advanced technologies to deliver the precision required for the science programme. In parallel, the development of the magnet technologies for the future hadron collider will be really exciting, particularly the potential use of high-temperature superconductors, as I said before.

It is always difficult to predict the specific “return on investment” on the technologies for big scientific research infrastructure. Part of this challenge is that some of that benefits might be 20, 30, 40 years down the line. Nevertheless, every retrospective that has tried, has demonstrated that you get a huge downstream benefit.

Do we reward technical innovation well enough in high-energy physics?

There needs to be a bit of a culture shift within our community. Engineering and technology innovation are critical to the future of science and critical to the prosperity of Europe. We should be striving to reward individuals working in these areas.

Should the field make it more flexible for physicists and engineers to work in industry and return to the field having worked there?

This is an important question. I actually think things are changing. The fluidity between academia and industry is increasing in both directions. For example, an early-career researcher in particle physics with a background in deep artificial-intelligence techniques is valued incredibly highly by industry. It also works the other way around, and I experienced this myself in my career when one of my post-doctoral researchers joined from an industry background after a PhD in particle physics. The software skills they picked up from industry were incredibly impactful.

I don’t think there is much we need to do to directly increase flexibility – it’s more about culture change, to recognise that fluidity between industry and academia is important and beneficial. Career trajectories are evolving across many sectors. People move around much more than they did in the past.

Does CERN have a future as a global laboratory?

CERN already is a global laboratory. The amazing range of nationalities working here is both inspiring and a huge benefit to CERN.

How can we open up opportunities in low- and middle-income countries?

I am really passionate about the importance of diversity in all its forms and this includes national and regional inclusivity. It is an agenda that I pursued in my last two positions. At the Deep Underground Neutrino Experiment, I was really keen to engage the scientific community from Latin America, and I believe this has been mutually beneficial. At STFC, we used physics as a way to provide opportunities for people across Africa to gain high-tech skills. Going beyond the training, one of the challenges is to ensure that people use these skills in their home nations. Otherwise, you’re not really helping low- and middle-income countries to develop.

What message would you like to leave with readers?

That we have really only just started the LHC programme. With more than a factor of 10 increase in data to come, coupled with new data tools and upgraded detectors, the High-Luminosity LHC represents a major opportunity for a new discovery. Its nature could be a complete surprise. That’s the whole point of exploring the unknown: you don’t know what’s out there. This alone is incredibly exciting, and it is just a part of CERN’s amazing future.

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Schwinger lined us up in his office, and spent several hours assigning thesis subjects. It was a remarkable performance. I was the last in line. Having run out of well-defined thesis problems, he explained to me that weak and electromagnetic interactions share two remarkable features: both are vectorial and both display aspects of universality. Schwinger suggested that I create a unified theory of the two interactions – an electroweak synthesis. How I was to do this he did not say, aside from slyly hinting at the Yang–Mills gauge theory.

By the summer of 1958, I had convinced myself that weak and electromagnetic interactions might be described by a badly broken gauge theory, and Schwinger that I deserved a PhD. I had hoped to partly spend a postdoctoral fellowship in Moscow at the invitation of the recent Russian Nobel laureate Igor Tamm, and sought to visit Niels Bohr’s institute in Copenhagen while awaiting my Soviet visa. With Bohr’s enthusiastic consent, I boarded the SS Île de France with my friend Jack Schnepps. Following a memorable and luxurious crossing – one of the great ship’s last – Jack drove south to Padova to work with Milla Baldo-Ceolin’s emulsion group in Padova, and I took the slow train north to Copenhagen. Thankfully, my Soviet visa never arrived. I found the SU(2) × U(1) structure of the electroweak model in the spring of 1960 at Bohr’s famous institute at Blegsdamvej 19, and wrote the paper that would earn my share of the 1979 Nobel Prize.

We called the new quark flavour “charm”, completing two weak doublets of quarks to match two weak doublets of leptons, and establishing lepton–quark symmetry, which holds to this day

A year earlier, in 1959, Augusto Gamba, Bob Marshak and Susumo Okubo had proposed lepton–hadron symmetry, which regarded protons, neutrons and lambda hyperons as the building blocks of all hadrons, to match the three known leptons at the time: neutrinos, electrons and muons. The idea was falsified by the discovery of a second neutrino in 1962, and superseded in 1964 by the invention of fractionally charged hadron constituents, first by George Zweig and André Petermann, and then decisively by Murray Gell-Mann with his three flavours of quarks. Later in 1964, while on sabbatical in Copenhagen, James Bjorken and I realised that lepton–hadron symmetry could be revived simply by adding a fourth quark flavour to Gell-Mann’s three. We called the new quark flavour “charm”, completing two weak doublets of quarks to match two weak doublets of leptons, and establishing lepton–quark symmetry, which holds to this day.

Annus mirabilis

1964 was a remarkable year. In addition to the invention of quarks, Nick Samios spotted the triply strange Ω^– baryon, and Oscar Greenberg devised what became the critical notion of colour. Arno Penzias and Robert Wilson stumbled on the cosmic microwave background radiation. James Cronin, Val Fitch and others discovered CP violation. Robert Brout, François Englert, Peter Higgs and others invented spontaneously broken non-Abelian gauge theories. And to top off the year, Abdus Salam rediscovered and published my SU(2) × U(1) model, after I had more-or-less abandoned electroweak thoughts due to four seemingly intractable problems.

Much to my surprise and delight, all of them would be solved within just a few years, with the last theoretical obstacle removed by Makoto Kobayashi and Toshihide Maskawa in 1973 (see “Four intractable problems” panel). A few months later, Paul Musset announced that CERN’s Gargamelle detector had won the race to detect weak neutral-current interactions, giving the electroweak model the status of a predictive theory. Remarkably, the year had begun with Gell-Mann, Harald Fritzsch and Heinrich Leutwyler proposing QCD, and David Gross, Frank Wilczek and David Politzer showing it to be asymptotically free. The Standard Model of particle physics was born.

Charmed findings

But where were the charmed quarks? Early on Monday morning on 11 November, 1974, I was awakened by a phone call from Sam Ting, who asked me to come to his MIT office as soon as possible. He and Ulrich Becker were waiting for me impatiently. They showed me an amazingly sharp resonance. Could it be a vector meson like the ρ or ω and be so narrow, or was it something quite different? I hopped in my car and drove to Harvard, where my colleagues Alvaro de Rújula and Howard Georgi excitedly regaled me about the Californian side of the story. A few days later, experimenters in Frascati confirmed the BNL–SLAC discovery, and de Rújula and I submitted our paper “Is Bound Charm Found?” – one of two papers on the J/ψ discovery printed in Physical Review Letters on 5 July 1965 that would prove to be correct. Among five false papers was one written by my beloved mentor, Julian Schwinger.

The second correct paper was by Tom Appelquist and David Politzer. Well before that November, they had realised (without publishing) that bound states of a charmed quark and its antiquark lying below the charm threshold would be exceptionally narrow due the asymptotic freedom of QCD. De Rújula suggested to them that such a system be called charmonium in an analogy with positronium. His term made it into the dictionary. Shortly afterward, the 1976 Nobel Prize in Physics was jointly awarded to Burton Richter and Sam Ting for “their pioneering work in the discovery of a heavy elementary particle of a new kind” – evidence that charm was not yet a universally accepted explanation. Over the next few years, experimenters worked hard to confirm the predictions of theorists at Harvard and Cornell by detecting and measuring the masses, spins and transitions among the eight sub-threshold charmonium states. Later on, they would do the same for 14 relatively narrow states of bottomonium.

Other experimenters were searching for particles containing just one charmed quark or antiquark. In our 1975 paper “Hadron Masses in a Gauge Theory”, de Rújula, Georgi and I included predictions of the masses of several not-yet-discovered charmed mesons and baryons. The first claim to have detected charmed particles was made in 1975 by Robert Palmer and Nick Samios at Brookhaven, again with a bubble-chamber event. It seemed to show a cascade decay process in which one charmed baryon decays into another charmed baryon, which itself decays. The measured masses of both of the charmed baryons were in excellent agreement with our predictions. Though the claim was not widely accepted, I believe to this day that Samios and Palmer were the first to detect charmed particles.

The SLAC electron–positron collider, operating well above charm threshold, was certainly producing charmed particles copiously. Why were they not being detected? I recall attending a conference in Wisconsin that was largely dedicated to this question. On the flight home, I met my old friend Gerson Goldhaber, who had been struggling unsuccessfully to find them. I think I convinced him to try a bit harder. A couple of weeks later in 1976, Goldhaber and François Pierre succeeded. My role in charm physics had come to a happy ending. 

• This article is adapted from a presentation given at the Institute of High-Energy Physics in Beijing on 20 October 2024 to celebrate the 50th anniversary of the discovery of the J/ψ.

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Ten years ago, Zhang helped organise the first CERN Webfest, a hackathon that explores creative uses of technology for science and society. Webfest helped Zhang develop his coding skills and knowledge of physics by applying it to something beyond his own discipline. He also made long-lasting connections with teammates, who were from different academic backgrounds and all over the world. After participating in more hackathons, Zhang’s growing “hacker spirit” inspired him to start his own company. In 2024 Zhang returned to Webfest not as a participant, but as the CEO of DoraHacks.

Hackathons are social coding events often spanning multiple days. They are inclusive and open – no academic institution or corporate backing is required – making them accessible to a diverse range of talented individuals. Participants work in teams, pooling their skills to tackle technical problems through software, hardware or a business plan for a new product. Physicists, computer scientists, engineers and entrepreneurs all bring their strengths to the table. Young scientists can pursue work that may not fit within typical research structures, develop their skills, and build portfolios and professional networks.

“If you’re really passionate about some­thing, you should be able to jump on a project and work on it,” says Zhang. “You shouldn’t need to be associated with a university or have a PhD to pursue it.”

For early-career researchers, hackathons offer more than just technical challenges. They provide an alternative entry point into research and industry, bridging the gap between academia and real-world applications. University-run hackathons often attract corporate sponsors, giving them the budget to rent out stadiums with hundreds, sometimes thousands, of attendees.

“These large-scale hackathons really capture the attention of headhunters and mentors from industry,” explains Zhang. “They see the events as a recruitment pool. It can be a really effective way to advance careers and speak to representatives of big companies, as well as enhancing your coding skills.”

In the 2010s, weekend hackathons served as Zhang’s stepping stone into entrepreneurship. “I used to sit in the computer-science common room and work on my hacks. That’s how I met most of my friends,” recalled Zhang. “But later I realised that to build something great, I had to effectively organise people and capital. So I started to skip my computer-science classes and sneak into the business classrooms.” Zhang would hide in the back row of the business lectures, plotting his plan towards entrepreneurship. He networked with peers to evaluate different business models each day. “It was fun to combine our knowledge of engineering and business theory,” he added. “It made the journey a lot less stressful.”

But the transition from science to entrepreneurship was hard. “At the start you must learn and do everything yourself. The good thing is you’re exposed to lots of new skills and new people, but you also have to force yourself to do things you’re not usually good at.”

This is a dilemma many entrepreneurs face: whether to learn new skills from scratch, or to find business partners and delegate tasks. But finding trustworthy business partners is not always easy, and making the wrong decision can hinder the start up’s progress. That’s why planning the company’s vision and mission from the start is so important.

“The solution is actually pretty straight forward,” says Zhang. “You need to spend more time completing the important milestones yourself, to ensure you have a feasible product. Once you make the business plan and vision clear, you get support from everywhere.”

Decentralised community governance

Rather than hackathon participants competing for a week before abandoning their code, Zhang started DoraHacks to give teams from all over the world a chance to turn their ideas into fully developed products. “I want hackathons to be more than a recruitment tool,” he explains. “They should foster open-source development and decentralised community governance. Today, a hacker from Tanzania can collaborate virtually with a team in the US, and teams gain support to develop real products. This helps make tech fields much more diverse and accessible.”

Zhang’s company enables this by reducing logistical costs for organisers and providing funding mechanisms for participants, making hackathons accessible to aspiring researchers beyond academic institutions. As the community expands, new doors open for young scientists at the start of their careers.

“The business model is changing,” says Zhang. Hackathons are becoming fundamental to emerging technologies, particularly in areas like quantum computing, blockchain and AI, which often start out open source. “There will be a major shift in the process of product creation. Instead of building products in isolation, new technologies rely on platforms and infrastructure where hackers can contribute.”

Today, hackathons aren’t just about coding or networking – they’re about pushing the boundaries of what’s possible, creating meaningful solutions and launching new career paths. They act as incubators for ideas with lasting impact. Zhang wants to help these ideas become reality. “The future of innovation is collaborative and open source,” he says. “The old world relies on corporations building moats around closed-source technology, which is inefficient and inaccessible. The new world is centred around open platform technology, where people can build on top of old projects. This collaborative spirit is what makes the hacker movement so important.”

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Born in 1926 to an intellectual family in Shanghai, Lee’s education was disrupted several times by the war against Japan. He neither completed high school nor graduated from university. In 1943, however, he took the national entrance exam and, with outstanding scores, was admitted to the chemical engineering department of Zhejiang University. He then transferred to the physics department of Southwest Associated University, a temporary setup during the war for Peking, Tsinghua and Nankai universities. In the autumn of 1946, under the recommendation of Ta-You Wu, Lee went to study at the University of Chicago under the supervision of Enrico Fermi, earning his PhD in June 1950.

From 1950 to 1953 Lee conducted research at the University of Chicago, the University of California, Berkeley and the Institute for Advanced Study, located in Princeton. During this period, he made significant contributions to particle physics, statistical mechanics, field theory, astrophysics, condensed-matter physics and turbulence theory, demonstrating a wide range of interests and deep insights in several frontiers of physics. In a 1952 paper on turbulence, for example, Lee pointed out the significant difference between fluid dynamics in two-dimensional and three-dimensional spaces, namely, there is no turbulence in two dimensions. This finding provided essential conditions for John von Neumann’s model, which used supercomputers to simulate weather.

Profound impact

During this period, Lee and Chen-Ning Yang collaborated on two foundational works in statistical physics concerning phase transitions, discovering the famous “unit circle theorem” on lattice gases, which had a profound impact on statistical mechanics and phase-transition theory.

Between 1952 and 1953, during a visit to the University of Illinois at Urbana-Champaign, Lee was inspired by discussions with John Bardeen (winner, with Leon Neil Cooper and John Robert Schrieffer, of the 1972 Nobel Prize in Physics for developing the first successful microscopic theory of superconductivity). Lee applied field-theory methods to study the motion of slow electrons in polar crystals, pioneering the use of field theory to investigate condensed matter systems. According to Schrieffer, Lee’s work directly influenced the development of their “BCS” theory of superconductivity.

In 1953, after taking an assistant professor position at Columbia University, Lee proposed a renormalisable field-theory model, widely known as the “Lee Model,” which had a substantial impact on the study of renormalisation in quantum field theory.

On 1 October 1956, Lee and Yang’s theory of parity non-conservation in weak interactions was published in Physical Review. It was quickly confirmed by the experiments of Chien-Shiung Wu and others, earning Lee and Yang the 1957 Nobel Prize in Physics – one of the fastest recognitions in the history of the Nobel Prize. The discovery of parity violation significantly challenged the established understanding of fundamental physical laws and directly led to the establishment of the universal V–A theory of weak interactions in 1958. It also laid the groundwork for the unified theory of weak and electromagnetic interactions developed a decade later.

In 1957, Lee, Oehme and Yang extended symmetry studies to combined charge–parity (CP) transformations. The CP non-conservation discovered in neutral K-meson decays in 1964 validated the importance of Lee and his colleagues’ theoretical work, as well as the later establishment of CP violation theories. The same year, Lee was appointed the Fermi Professor of Physics at Columbia.

In the 1970s, Lee published papers exploring the origins of CP violation, suggesting that it might stem from spontaneous symmetry breaking in the vacuum and predicting several significant phenomenological consequences. In 1974, Lee and G C Wick investigated whether spontaneously broken symmetries in the vacuum could be partially restored under certain conditions. They found that heavy-ion collisions could achieve this restoration and produce observable effects. This work pioneered the study of the quantum chromodynamics (QCD) vacuum, phase transitions and quark–gluon plasma. It also laid the theoretical and experimental foundation for relativistic heavy-ion collision physics.

From 1982, Lee devoted significant efforts to solving non-perturbative QCD using lattice-QCD methods. Together with Norman Christ and Fred Friedberg, he developed stochastic lattice field theory and promoted first-principle lattice simulations on supercomputers, greatly advancing lattice QCD research.

Immense respect

In 2011 Lee retired as a professor emeritus from Columbia at the age of 85. In China, he enjoyed immense respect, not only for being the first Chinese scientist (with Chen-Ning Yang) to win a Nobel Prize, but also for enhancing the level of science and education in China and promoting the Sino-American collaboration in high-energy physics. This led to the establishment and successful construction of China’s first major high-energy physics facility, the Beijing Electron–Positron Collider (BEPC). At the beginning of this century, Lee supported and personally helped the upgrade of BEPC, the Daya Bay reactor neutrino experiment and others. In addition, he initiated, promoted and executed the China–US Physics Examination and Application plan, the National Natural Science Foundation of China, and the postdoctoral system in China.

Tsung-Dao Lee’s contributions to an extraordinarily wide range of fields profoundly shaped humanity’s understanding of the basic laws of the universe.

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Robert Aymar was educated at École Poly­technique in Paris. He started his career in plasma physics at the Commissariat à l’Énergie Atomique (CEA), since renamed the Commissariat à l’Énergie Atomique et aux Énergies Alternatives, at the time when thermonuclear fusion was declassified and research started on its application to energy production. After being involved in several studies at CEA, Aymar contributed to the design of the Joint European Torus, the European tokamak project based on conventional magnet technology, built in Culham, UK in the late 1970s. In the same period, CEA was considering a compact tokamak project based on superconducting magnet technology, for which Aymar decided to use pressurised superfluid helium cooling – a technology then recently developed by Gérard Claudet and his team at CEA Grenoble. Aymar was naturally appointed head of the Tore Supra tokamak project, built at CEA Cadarache from 1977 to 1988. The successful project served inter alia as an industrial-sized demonstrator of superfluid helium cryogenics, which became a key technology of the LHC.

As head of the Département des Sciences de la Matière at CEA from 1990 to 1994, Aymar set out to bring together the physics of the infinitely large and the infinitely small, as well as the associated instrumentation, in a department that has now become the Institut de Recherche sur les Lois Fondamentales de l’Univers. In that position, he actively supported CEA–CERN collaboration agreements on R&D for the LHC and served on many national and international committees. In 1993 he chaired the LHC external review committee, whose recommendation proved decisive in the project’s approval. From 1994 to 2003 he led the ITER engineering design activities under the auspices of the International Atomic Energy Agency, establishing the basic design and validity of the project that would be approved for construction in 2006. In 2001, the CERN Council called on his expertise once again by entrusting him to chair the external review committee for CERN’s activities.

When Robert Aymar took over as Director-General of CERN in 2004, the construction of the LHC was well under way. But there were many industrial and financial challenges, and a few production crises still to overcome. During his tenure, which saw the ramp-up, series production and installation of major components, the machine was completed and the first beams circulated. That first start-up in 2008 was followed by a major technical problem that led to a shutdown lasting several months. But the LHC had demonstrated that it could run, and in 2009 the machine was successfully restarted. Aymar’s term of office also saw a simplification of CERN’s structure and procedures, aimed at making the laboratory more efficient. He also set about reducing costs and secured additional funding to complete the construction and optimise the operation of the LHC. After retirement, he remained active as a scientific advisor to the head of the CEA, occasionally visiting CERN and the ITER construction site in Cadarache.

Robert Aymar was a dedicated and demanding leader, with a strong drive and search for pragmatic solutions in the activities he undertook or supervised. CERN and the LHC project owe much to his efforts. He was also a man of culture with a marked interest in history. It was a privilege to serve under his direction.

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Theoretical physicist James D “BJ” Bjorken, whose work played a key role in revealing the existence of quarks, passed away on 6 August aged 90. Part of a wave of young physicists who came to Stanford in the mid-1950s, Bjorken also made important contributions to the design of experiments and the efficient operation of accelerators.

Born in Chicago on 22 June 1934, James Daniel Bjorken grew up in Park Ridge, Illinois, where he was drawn to mathematics and chemistry. His father, who had immigrated from Sweden in 1923, was an electrical engineer who repaired industrial motors and generators. After earning a bachelor’s degree at MIT, he went to Stanford University as a graduate student in 1956. He was one of half a dozen MIT physicists, including his adviser Sidney Drell and future director of the SLAC National Accelerator Laboratory Burton Richter, who were drawn by new facilities on the Stanford campus. This included an early linear accelerator that scattered electrons off targets to explore the nature of the neutron and proton.

Ten years later those experiments moved to SLAC, where the newly constructed Stanford Linear Collider would boost electrons to much higher energies. By that time, theorists had proposed that protons and neutrons contained fundamental particles. But no one knew much about their properties or how to go about proving they were there. Bjorken, who joined the Stanford faculty in 1961, wrote an influential 1969 paper in which he suggested that electrons were bouncing off point-like particles within the proton, a process known as deep inelastic scattering. He started lobbying experimentalists to test it with the SLAC accelerator.

Carrying out the experiments would require a new mathematical language and Bjorken contributed to its development, with simplifications and improvements from two of his students (John Kogut and Davison Soper) and Caltech physicist Richard Feynman. In the late 1960s and early 1970s, those experiments confirmed that the proton does indeed consist of fundamental particles – a discovery honoured with the 1990 Nobel Prize in Physics for SLAC’s Richard Taylor and MIT’s Henry Kendall and Jerome Friedman. Bjorken’s role was later recognised by the prestigious Wolf Prize in Physics and the 2015 High Energy and Particle Physics Prize of the European Physical Society.

While the invention of “Bjorken scaling” was his most famous scientific achievement, Bjorken was also known for identifying a wide variety of interesting problems and tackling them in novel ways. He was somewhat iconoclastic. He also had colourful and often distinctly visual ways of thinking about physics – for instance, describing physics concepts in terms of plumbing or a baked Alaska. He never sought recognition for himself and was very generous in recognising the contributions of others.

In 1979 Bjorken headed east to become associate director for physics at Fermilab. He returned to SLAC in 1989, where he continued to innovate. Over the course of his career, among other things, he invented ideas related to the existence of the charm quark and the circulation of protons in a storage ring. He helped popularise the unitarity triangle and, along with Drell, co-wrote the widely used graduate-level textbooks Relativistic Quantum Mechanics and Relativistic Quantum Fields. In 2009 Bjorken contributed to an influential paper by three younger theorists suggesting approaches for searching for “dark” photons, hypothetical carriers of a new fundamental force.

He was also awarded the American Physical Society’s Dannie Heineman Prize, the Department of Energy’s Ernest Orlando Lawrence Award, and the Dirac Medal from the International Center for Theoretical Physics. In 2017 he shared the Robert R Wilson Prize for Achievement in the Physics of Particle Accelerators for groundbreaking theoretical work he did at Fermilab that helped to sharpen the focus of particle beams in many types of accelerators.

Known for his warmth, generosity and collaborative spirit, Bjorken passionately pursued many interests outside physics, from mountain climbing, skiing, cycling and windsurfing to listening to classical music. He divided his time between homes in Woodside, California and Driggs, Idaho, and thought nothing of driving long distances to see an opera in Chicago or dropping in unannounced at the office of some fellow physicist for deep conversations about general relativity, dark matter or dark energy – once remarking: “I’ve found the most efficient way to test ideas and get hard criticism is one-on-one conversation with people who know more than I do.”

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Born in Berlin in 1951, Max earned his diploma in physics in 1973 from Humboldt University of Berlin (HUB, East-Germany, GDR) with a thesis on low-energy heavy-ion physics. He received his PhD in 1977 from the Institute for High Energy Physics (IHEP) of the Academy of Sciences of the GDR in Zeuthen (now part of DESY) on the subject of multiparticle production, and his habilitation degree in 1984 from HUB. From 1973 to 1991 he conducted research at IHEP Zeuthen, spending several years from 1977 at the Joint Institute for Nuclear Research in Dubna, and from the 1980s at DESY and CERN. For his role in determining the asymmetry of the interaction of polarised positive and negative muons with the NA4 muon spectrometer at CERN’s SPS M2 muon beam, he was awarded the Max von Laue Medal by the Academy of Sciences of the GDR in 1985.

Max worked as a scientist at DESY from 1992 to 2006. As a member of the H1 experiment at the lepton–proton collider HERA since 1985, his research focused on investigating the internal structure of protons using deep inelastic scattering. He served as spokesperson of the H1 collaboration from 2002 to 2006 for two mandates.

Max became a professor at the University of Liverpool in 2006, and the following year he joined the ATLAS collaboration. He served as chair of the ATLAS publication committee and as editorial-board chair of the ATLAS detector paper and other important works. Max made key contributions to data analysis, notably on the high-precision 7 TeV inclusive W and Z boson production cross sections and associated properties, and was a convener of the PDF forum in 2015–2016. From 2017 to 2019, Max was chair of the ATLAS collaboration board, during which he made invaluable contributions to the experiment and collaboration life. He led the Liverpool ATLAS team from 2009 to 2017. Under his guidance, the 30-strong group contributed to the maintenance of the SCT detector, as well as to ATLAS data preparation and physics analyses. The group also developed hybrids, mechanics and software for the new ITk pixel and strip detectors.

In recent years, Max’s scientific contributions extended well beyond ATLAS. He was a strong advocate for the development of an electron-beam upgrade of the LHC, the LHeC, and collaborated closely with the CERN accelerator group and international teams on the development of energy-recovery linacs. Here, he was influential in the development of the PERLE demonstrator accelerator at IJCLab, for which he acted as spokesperson until 2023.

A strong advocate for the responsibility of scientists toward their societies

In 2013 Max was awarded the Max Born Prize by the Deutsche Physikalische Gesellschaft and the UK Institute of Physics for his fundamental experimental contributions to the elucidation of the proton structure using deep-inelastic scattering. The prize citation stands as a testament to his scientific stature: “In the last 40 years, Max Klein has dedicated himself to the study of the innermost structure of the proton. In the 1990s he was a leading figure in the discovery that gluons form a surprisingly large component of proton structure. These gluons play an important role in the production of Higgs bosons in proton–proton collisions for which experiments at CERN have recently found promising candidates.”

Besides being a distinguished scientist, Max was a man of unwavering principles, grounded in his selfless interactions with others and his deep sense of humanity. Drawing from his experience as a bridge between East and West, he was a strong advocate for international scientific collaboration and the responsibility of scientists toward their societies. He had a strong desire and ability to mentor and support students, postdocs and early-career researchers, and an admirably wise and calm approach to problem solving.

Max Klein had a profound knowledge of physics and a tireless dedication to ATLAS and to experimental particle physics in general. His passing is a profound loss for the entire community, but his legacy will endure.

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Experimental particle physicist Ian Shipsey, a remarkable leader and individual, passed away suddenly and unexpectedly in Oxford on 7 October.

Ian was educated at Queen Mary University of London and the University of Edinburgh, where he earned his PhD in 1986 for his work on the NA31 experiment at CERN. Moving to the US, he joined Syracuse as a post-doc and then became a faculty member at Purdue, where, in 2007, he was elected Julian Schwinger Distinguished Professor of Physics. In 2013 he was appointed the Henry Moseley Centenary Professor of Experimental Physics at the University of Oxford.

Ian was a central figure behind the success of the CLEO experiment at Cornell, which was for many years the world’s pre-eminent detector in flavour physics. He led many analyses, most notably in semi-leptonic decays, from which he measured four different CKM matrix elements, and oversaw the construction of the silicon vertex detector for the CLEO III phase of the experiment. He served as co-spokesperson between 2001 and 2004, and was one of the intellectual leaders that saw the opportunity to re-configure the detector and the CESR accelerator as a facility for making precise exploration of physics at the charm threshold. The resulting CLEO-c programme yielded many important measurements in the charm system and enabled critical experimental validations of lattice–QCD predictions.

Influential voice

At CMS, Ian played a leading role in the construction of the forward-pixel detector, exploiting the silicon laboratory he had established at Purdue. His contributions to CMS physics analy­ses were no less significant. These included the observation of upsilon suppression in heavy-ion collisions (a smoking gun for the production of quark–gluon plasma) and the discovery, reported in a joint Nature paper with the LHCb collaboration, of the ultra-rare decay B_s → μ⁺μ^–. He was also an influential voice as CMS collaboration board chair (2013–2014).

After moving to the University of Oxford and, in 2015, joining the ATLAS collaboration, Ian became Oxford’s ATLAS team leader and established state-of-the-art cleanrooms, which are used for the construction of the future inner tracker (ITk) pixel end-cap modules. Together with his students, he contributed to measurements of the Higgs boson mass and width, and to the search for its rare di-muon decay. Ian also led the UK’s involvement in LSST (now the Vera Rubin Observatory), where Oxford is providing deep expertise for the CCD cameras.

Following his tenure as the dynamic head of the particle physics sub-department, Ian was elected head of Oxford physics in 2018 and re-elected in 2023. Among his many successful initiatives, he played a leading role in establishing the £40 million UKRI “Quantum Technologies for Fundamental Physics” programme, which is advancing quantum-based applications across various areas of physics. With the support of this programme, he led the development of novel atom interferometers for light dark matter searches and gravitational-wave detection.

Ian took a central role in establishing roadmaps for detector R&D both in the US and (via ECFA) in Europe. He was one of the coordinators and driving force of the ECFA R&D roadmap panel, and co-chair of the US effort to define the basic research needs in this area. As chair of the ICFA instrumentation, innovation and development panel, he promoted R&D in instrumentation for particle physics and the recognition of excellence in this field.

Among his many prestigious honours, Ian was elected a Fellow of the Royal Society in 2022 and received the James Chadwick Medal and Prize from the Institute of Physics in 2019. He served on numerous collaboration boards, panels, and advisory and decision-making committees shaping national and international science strategies.

The success of Ian’s career is even more remarkable given that he lost his hearing in 1989. He received a cochlear implant, which restored limited auditory ability, and gave unforgettable talks on this subject, explaining the technology and its impact on his life.

Ian was an outstanding physicist and also a remarkable individual. His legacy is not only an extensive body of transformative scientific results, but also the impact that he had on all who met him. He was equally charming, whether speaking to graduate students or lab directors. Everyone felt better after talking to Ian. His success derived from a remarkable combination of optimism and limitless energy. Once he had identified the correct course of action, he would not allow himself to be dissuaded by cautious pessimists who worried about the challenges ahead. His colleagues and many graduate students will continue to benefit for many years from the projects he initiated. The example he set as a physicist, and the memories he leaves as friend, will endure still longer.

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What role does science communication play in your academic career?

When I was a postdoc I started to realise that the science communication side of my life was really important to me. It felt like I was having a big impact – and in research, you don’t always feel like you’re having that big impact. When you’re a grad student or postdoc, you spend a lot of time dealing with rejection, feeling like you’re not making progress or you’re not good enough. I realised that with science communication, I was able to really feel like I did know something, and I was able to share that with people.

When I began to apply for faculty jobs, I realised I didn’t want to just do science writing as a nights and weekends job, I wanted it to be integrated into my career. Partially because I didn’t want to give up the opportunity to have that kind of impact, but also because I really enjoyed it. It was energising for me and helped me contextualise the work I was doing as a scientist.

How did you begin your career in science communication?

I’ve always enjoyed writing stories and poetry. At some point I figured out that I could write about science. When I went to grad school I took a class on science journalism and the professor helped me pitch some stories to magazines, and I started to do freelance science writing. Then I discovered Twitter. That was even better because I could share every little idea I had with a big audience. Between Twitter and freelance science writing, I garnered quite a large profile in science communication and that led to opportunities to speak and do more writing. At some point I was approached by agents and publishers about writing books.

Who is your audience?

When I’m not talking to other scientists, my main community is generally those who have a high-school education, but not necessarily a university education. I don’t tailor things to people who aren’t interested in science, or try to change people’s minds on whether science is a good idea. I try to help people who don’t have a science background feel empowered to learn about science. I think there are a lot of people who don’t see themselves as “science people”. I think that’s a silly concept but a lot of people conceptualise it that way. They feel like science is closed to them.

The more that science communicators can give people a moment of understanding, an insight into science, I think they can really help people get more involved in science. The best feedback I’ve ever gotten is when students have come up to me and said “I started studying physics because I followed you on Twitter and I saw that I could do this,” or they read my book and that inspired them. That’s absolutely the best thing that comes out of this. It is possible to have a big impact on individuals by doing social media and science communication – and hopefully change the situation in science itself over time.

What were your own preconceptions of academia?

I have been excited about science since I was a little kid. I saw that Stephen Hawking was called a cosmologist, so I decided I wanted to be a cosmologist too. I had this vision in my head that I would be a theoretical physicist. I thought that involved a lot of standing alone in a small room with a blackboard, writing equations and having eureka moments. That’s what was always depicted on TV: you just sit by yourself and think real hard. When I actually got into academia, I was surprised by how collaborative and social it is. That was probably the biggest difference between expectation and reality.

How do you communicate the challenges of academia, alongside the awe-inspiring discoveries and eureka moments?

I think it’s important to talk about what it’s really like to be an academic, in both good ways and bad. Most people outside of academia have no idea what we do, so it’s really valuable to share our experiences, both because it challenges stereotypes in terms of what we’re really motivated by and how we spend our time, but also because there are a lot of people who have the same impression I did: where you just sit alone in a room with a chalkboard. I believe it’s important to be clear about what you actually do in academia, so more people can see themselves happy in the job.

At the same time, there are challenges. Academia is hard and can be very isolating. My advice for early-career researchers is to have things other than science in your life. As a student you’re working on something that potentially no one else cares very much about, except maybe your supervisor. You’re going to be the world-expert on it for a while. It can be hard to go through that and not have anybody to talk to about your work. I think it’s important to acknowledge what people go through and encourage them to get support.

There are of course other parts of academia that can be really challenging, like moving all the time. I went from West coast to East coast between undergrad and grad school, and then from the US to the UK, from the UK to Australia, back to the US and then to Canada. That’s a lot. It’s hard. They’re all big moves so you lose whatever local support system you had and you have to start over in a new place, make new friends and get used to a whole new government bureaucracy.

So there are a whole lot of things that are difficult about academia, and you do need to acknowledge those because a lot of them affect equity. Some of these make it more challenging to have diversity in the field, and they disproportionately affect some groups more than others. It is important to talk about these issues instead of just sweeping people under the rug.

Do you think that social media can help to diversify science and research?

Yes! I think that a large reason why people from underrepresented groups leave science is because they lack the feeling of belonging. If you get into a field and don’t feel like you belong, it’s hard to power through that. It makes it very unpleasant to be there. So I think that one of the ways social media can really help is by letting people see scientists who are not the stereotypical old white men. Talking about what being a scientist is really like, what the lifestyle is like, is really helpful for dismantling those stereotypes.

Your first book, The End of Everything, explored astrophysics but your next will popularise particle physics. Have you had to change your strategy when communicating different subjects?

This book is definitely a lot harder to write. The first one was very big and dramatic: the universe is ending! In this one, I’m really trying to get deeper into how fundamental physics works, which is a more challenging story to tell. The way I’m framing it is through “how to build a universe”. It’s about how fundamental physics connects with the structure of reality, both in terms of what we experience in our daily lives, but also the structure of the universe, and how physicists are working to understand that. I also want to highlight some of the scientists who are doing that work.

So yes, it’s much harder to find a catchy hook, but I think the subject matter and topics are things that people are curious about and have a hunger to understand. There really is a desire amongst the public to understand what the point of studying particle physics is.

Is high-energy physics succeeding when it comes to communicating with the public?

I think that there are some aspects where high-energy physics does a fantastic job. When the Higgs boson was discovered in 2012, it was all over the news and everybody was talking about it. Even though it’s a really tough concept to explain, a lot of people got some inkling of its importance.

A lot of science communication in high-energy physics relies on big discoveries, however recently there have not been that many discoveries at the level of international news. There have been many interesting anomalies in recent years, however in terms of discoveries we had the Higgs and the neutrino mass in 1998, but I’m not sure that there are many others that would really grab your attention if you’re not already invested in physics.

Part of the challenge is just the phase of discovery that particle physics is in right now. We have a model, and we’re trying to find the edges of validity of that model. We see some anomalies and then we fix them, and some might stick around. We have some ideas and theories but they might not pan out. That’s kind of the story we’re working with right now, whereas if you’re looking at astronomy, we had gravitational waves and dark energy. We get new telescopes with beautiful pictures all the time, so it’s easier to communicate and get people excited than it is in particle physics, where we’re constantly refining the model and learning new things. It’s a fantastically exciting time, but there have been no big paradigm shifts recently.

How can you keep people engaged in a subject where big discoveries aren’t constantly being made?

I think it’s hard. There are a few ways to go about it. You can talk about the really massive journey we’re on: this hugely consequential and difficult challenge we’re facing in high-energy physics. It’s a huge task of massive global effort, so you can help people feel involved in the quest to go beyond the Standard Model of particle physics.

You need to acknowledge it’s going to be a long journey before we make any big discoveries. There’s much work to be done, and we’re learning lots of amazing things along the way. We’re getting much higher precision. The process of discovery is also hugely consequential outside of high-energy physics: there are so many technological spin-offs that tie into other fields, like cosmology. Discoveries are being made between particle and cosmological physics that are really exciting.

Every little milestone is an achievement to be celebrated

We don’t know what the end of the story looks like. There aren’t a lot of big signposts along the way where we can say “we’ve made so much progress, we’re halfway there!” Highlighting the purpose of discovery, the little exciting things that we accomplish along the way such as new experimental achievements, and the people who are involved and what they’re excited about – this is how we can get around this communication challenge.

Every little milestone is an achievement to be celebrated. CERN is the biggest laboratory in the world. It’s one of humanity’s crowning achievements in terms of technology and international collaboration – I don’t think that’s an exaggeration. CERN and the International Space Station. Those two labs are examples of where a bunch of different countries, which may or may not get along, collaborate to achieve something that they can’t do alone. Seeing how everyone works together on these projects is really inspiring. If more people were able to get a glimpse of the excitement and enthusiasm around these experiments, it would make a big difference.

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Cristiana Peroni, former team leader of the Torino group of the CMS collaboration, passed away on 19 June 2024.

Peroni obtained her degree in physics in 1974 at the University of Torino. She worked at an experiment on low-energy proton–antiproton collisions at the CERN Proton Synchrotron, before joining the European Muon Collaboration and, later, the New Muon Collaboration. After this, she moved to ZEUS at DESY and then CMS at the LHC, and was appointed full professor at the University of Torino in 2001.

Thanks to Cristiana’s initiative, in collaboration with Fabrizio Gasparini (project manager of the drift-tube project of CMS’s muon system), the Torino group joined the CMS collaboration in the late 1990s. The group took responsibility for the construction of the MB4 muon chambers, together with groups at Padua, Madrid and Aachen, which were responsible for the construction of the MB3, MB2 and MB1 layers of CMS’s drift-tube system, respectively.

At the same time, Cristiana started a collaboration with the JINR–Dubna group led by Igor Golutvin to realise a critical part of the system: the deposition of the field electrodes on the aluminium planes that form the structural element of the chambers. This was a very successful collaboration, in spite of the crucial issues related to complex logistics, which worked extremely well, guaranteeing the construction of the system within the required timeframe. Alongside hardware commitments, the team coordinated by Cristiana took on important roles of responsibility in the physics groups of the collaboration (in particular in the Higgs sector), and soon saw its expansion with the addition and merger of other groups in Torino, which added activities related to the tracker, electromagnetic calorimeter and precision proton spectrometer.

“Cris” was a determined and capable leader, highly appreciated for the attention she always paid to the professional growth of her collaborators, the career development of early-stage researchers, as well as the team building and mutual support that made her group united and coherent.

In the last part of her professional life, Cris turned her attention to research in medical physics, leaving the management of the CMS group to her collaborators, and carrying out research on hadron therapy. In this field, not only did she establish a new course on medical physics at Torino, but she was instrumental to the CNAO hadron-therapy facility in Pavia, which has been treating cancer patients for more than a decade.

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Sachio Komamiya, a prominent figure in the Japanese and International Linear Collider communities, passed away on 5 June 2024 at the age of 71.

Born in Yokohama, Japan in 1952, Komamiya graduated from the University of Tokyo in 1976. He remained there as a graduate student, under the mentorship of Masatoshi Koshiba. Komamiya began his diverse international career by proposing an experiment using the PETRA electron–positron collider at DESY in collaboration with Heidelberg University and the University of Manchester. This collaboration led to the JADE experiment. Koshiba’s laboratory took charge of developing the lead–glass electromagnetic shower detector, which operated reliably and contributed to the discovery of gluons.

After obtaining his PhD for his work at DESY, Komamiya took up a postdoc position at the University of Heidelberg, joining the group of Joachim Heintze. He quickly integrated himself into the group and to the JADE collaboration in general, and was one of the first to perform searches for supersymmetric particles – his enthusiasm for this type of analysis earning him the nickname “SachiNo”.

In 1986 Komamiya’s interest in the highest-energy experiments led him to SLAC as a staff physicist. The construction of the SLAC Linear Collider (SLC) – the first linear collider – was underway. The SLC was a single-pass collider that used a linac to accelerate both electrons and positrons, a design that was highly complex. Komamiya worked on developing the arcs that bent the beams at the end of the linac, which was one of the most complicated parts of the machine. Physics measurements at the SLC started in 1988 with the Mark II detector, and in 1990 Komamiya moved to Europe to join the OPAL experiment at the Large Electron Positron Collider.

Komamiya returned to Japan in 1999 and became a director of the International Center for Elementary Particle Physics at the University of Tokyo in 2000. While leading research and experiments there, he led Japan’s high-energy physics community, serving four terms as the chairman of the Japan Association of High Energy Physics and as a Japanese representative for the International Committee for Future Accelerators from 2000. His leadership and extensive international experience have been precious in advancing the International Linear Collider (ILC) project. In December 2012, a technical design report for the ILC was completed. Shortly afterwards, the ILC project was reorganised under the umbrellas of the Linear Collider Collaboration (LCC), led by Lyn Evans for project development, and the Linear Collider Board, which oversaw the LCC’s activity and was chaired by Komamiya.

Komamiya was eager to see the ILC become Japan’s first globally hosted project. He served as a diplomat to advance this vision, and was calm and patient when explaining to others the often-complex relations involved. Sachio thus fulfilled a critical and essential role bridging science and politics – a talent that, alongside his physics expertise, will be sorely missed.

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Hans started his academic career in atomic and nuclear physics in Munich, under the guidance of Heinz Maier-Leibnitz. A highlight was the discovery and precise measurement of shape isomerism in heavy nuclei. His observation of distinct rotational bands in plutonium-240 showed, for the first time, that nuclei can be in a strongly deformed cigar-shaped state shortly before fission, confirming the concept of a “double-humped” fission barrier. In Munich, and later in Heidelberg, he developed several innovative large-scale detectors for fission fragments and reaction products of heavy-ion collisions, becoming one of the leading experimentalists in the new field of heavy-ion physics, with experiments at the MPI for Nuclear Physics in Heidelberg and at the newly founded GSI in Darmstadt.

In the early 1980s, Hans reoriented his research towards the higher energies available at CERN. His contributions and advocacy, alongside a handful of other enthusiastic proponents, were instrumental in establishing CERN’s ultra-relativistic heavy-ion programme at the SPS, which was approved in 1984. He became the spokesperson of a first-generation heavy-ion experiment (Helios/NA34-2), initiator and spokesperson of a second-generation experiment (CERES/NA45), and a crucial supporter of the third-generation ALICE experiment at the LHC.

Hans was a brilliant experimentalist with a keen eye for cutting-edge detector concepts and how to apply them in a minimalistic approach. This was apparent in his masterpiece, the dilepton experiment CERES, which used a “hadron blind” double Cherenkov detector and a specially crafted magnetic field configuration to pick out and measure the rare electrons from the haystack of hadrons.

Initially with CERES, and later as a leading force within NA60, Hans succeeded in detecting, for the first time, thermally produced lepton pairs in heavy-ion collisions; the original discovery with NA45 remains one of the most cited papers from the SPS heavy-ion programme. The high-precision measurements at NA60 of what is arguably one of the most challenging signals (the Planck-like spectrum of thermal radiation at higher masses), and the precise characterisation of the in-medium modification of the ρ meson at lower masses, proved to be crucial in establishing the existence and properties of quark–gluon plasma. The enduring quality and relevance of these measurements remain unsurpassed almost two decades later.

Throughout his career, Hans held numerous positions in the realm of science policy at a variety of German and international research institutes. At CERN, he served as chair of the PSCC committee and as a member of the SPC. He was also a founding member of the first board of directors of the theory institute ECT* in Trento, a place that held special significance for him.

Hans was a brilliant experimentalist with a keen eye for cutting-edge detector concepts

As scientific director of GSI from 1992 to 1999, Hans set the course for the development and application of a groundbreaking innovation in radiation medicine: ion-beam cancer therapy. A pilot project at GSI for the irradiation of tumours with carbon-12 ions successfully treated 450 patients and led to the establishment of the Heidelberg Ion-Beam Therapy Center, the first European ion-beam therapy facility. Reflecting on his achievements, he was most proud of his contributions to ion-beam therapy. Additionally, Hans initiated discussions on the long-term future of GSI, which eventually led to the proposal for the international FAIR facility.

Hans also had a profound interest in the intersection of physics, music and neuroscience, collaborating with Hans-Günter Dosch on understanding perception of music and its physiological bases. This transdisciplinary approach produced highly cited publications on the differences in the auditory cortex between musicians and non-musicians, expanding the boundaries of how we understand the brain and its response to music.

Hans was an outstanding teacher, a prolific mentor, a successful science manager, but foremost, he was someone who profoundly loved physics, with a relentless drive to follow wherever his interests and research would lead him. His frequent and spirited commutes between Heidel­berg and CERN in his iconic green Lotus Elan will be fondly remembered. His critical guidance and profound questions will be deeply missed by all who had the privilege of knowing him.

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A student of Paul Scherrer at ETH Zurich, Werner obtained his PhD in 1960 with a thesis on two-photon transitions in barium-137 and moved to CERN, joining the “Groupe Chambre Wilson” (a collaboration of teams from CERN, ETH Zurich and Imperial College London). Around that time, cloud chambers were being replaced with spark chambers. Werner, already very experienced in electronics despite his young age, designed and built the entire trigger system for spark chambers from scratch using discrete components (NIM modules were not yet available at the time!).

In the late 1960s Werner started working on the OMEGA project – a high-aperture electronic spectrometer to be installed on a PS beam line in the West Area. The spectrometer was envisioned to operate as a facility, with a standard suite of detectors that could be complemented by experiment-specific apparatus provided by the individual collaborations. This was achieved by a large (3 m diameter) superconducting magnet equipped with spark chambers, a triggering system and data acquisition. The original programme included missing-mass experiments, the study of baryon-exchange processes and leptonic hyperon decays, and experiments with hyperon beams and with polarised targets. After a few years, interest moved to new topics, such as photoproduction, charm production and QCD studies.

In 1976 the OMEGA spectrometer was moved to its final position in the West Area on a beam line from the newly built SPS. In 1979, under Werner’s supervision, the spectrometer – until then equipped with spark chambers and plumbicon cameras – was instrumented with the new, much faster and higher resolution multi-wire proportional chambers. The refurbished OMEGA quickly became the go-to facility for a wide range of experiments. Over the years, under Werner’s stewardship, the facility was continuously upgraded with new equipment such as drift chambers, ring-imaging Cherenkov detectors, silicon microstrips and silicon pixel detectors (which were deployed at OMEGA for the first time). Triggering and data acquisition were also continuously updated such that, throughout its 25-year lifetime, OMEGA remained at the forefront of technology. It hosted some 50 experiments, with achievements ranging from its essential role in the establishment of non-qq mesons, to the detection of a (so-far unexplained) excess in the production of soft photons, to the observation of clear violations of factorisation in charm hadroproduction. The OMEGA scientific programme culminated in a key contribution to the discovery of quark–gluon plasma (QGP), with the detection of the signature enhancement pattern of strange and multi-strange hadrons in lead–lead collisions.

Werner retired from CERN in 1995, one year before OMEGA was closed, not because it had reached its time (QGP studies, then in full blossom, had to be hastily moved to the North Area), but to make room for an assembly and test facility for the LHC magnets. Throughout its lifetime, Werner truly was the “soul” of the OMEGA experiment, always present and ready to help. Swapping from one layout to the next (and from one experimental group to the next) was the standard way of operating, and Werner and his team had the heavy responsibility of keeping the spectrometer in good shape and guaranteeing a prompt and efficient restart of the experiments. Werner’s kind and thoughtful attitude was key to this and the many other OMEGA successes. His impassioned, matter-of-fact and selfless way of doing science influenced generations of physicists whose careers were forged at OMEGA. Werner coming into the control room and offering a basket of fruits from his garden remains vivid in the memory. We miss him dearly.

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Olav Ullaland, a brilliant detector physicist who spent his career at CERN, passed away on 16 June 2024.

Olav obtained his degree in particle physics at the University of Bergen in 1971. After a short period at Rutherford Appleton Laboratory in the UK, he went to CERN as a fellow in 1973, following which he was awarded a staff contract. He worked as a detector physicist at CERN until he retired in 2009, remaining active for several years as an emeritus. One of his last scientific articles dates from 2020.

Alongside detector R&D, Olav participated in several key CERN experiments. For the Split Field Magnet Detector, located at CERN’s Intersecting Storage Rings, he was in charge of the multi-wire proportional chambers and worked on the prototype of a novel electromagnetic calorimeter that was later adopted by the DELPHI experiment.

After contributing to the UA1 upgrade, he was asked to take a leading role in the complex barrel ring-imaging Cherenkov (RICH) project of DELPHI, which was the first attempt to integrate an imaging Cherenkov detector into a cylindrical collider experiment. The challenges were immense, as it was necessary to operate a gas and liquid radiator, together with a photo­sensitive gas, at different temperatures in a confined space. Thanks to Olav’s perseverance and the loyalty he inspired in his team, he was able to bring the apparatus to a level where it could be used in physics analysis, for example in the tagging of strange jets from Z and W decays. This was a critical milestone in the history of RICH detectors.

Around 1997 Olav joined LHCb and became a leader in the international effort to make its two RICH detectors a reality. Thanks to his deep knowledge of the many facets of detector physics and techniques, and his ability to remain calm, he and his team managed to find solutions to potential showstoppers. It is testament to Olav’s efforts that the particle identification system of LHCb works so impressively in the study of CP violation and heavy-flavour rare decays. In addition, Olav was the LHCb resource coordinator for several years, taking impeccable control of delicate LHCb financial matters at the beginning of the experiment operations. His expertise in leading many project reviews and trouble-shooting several wide-ranging detector subsystems was also in high demand both within and outside LHCb.

Olav was a wonderful collaborator. He was passionate in his support of students and fellows, and encouraged young people to give presentations and international talks, always graciously stepping away from the limelight himself. His dedication to student training was highlighted by his running of the CERN summer student programme, with both lectures and laboratory courses.

For Olav, work did not finish at CERN, but would be continued in any possible meeting place. These unconventional settings provided a conducive atmosphere to explore, discuss and challenge new projects and ideas, with the goal of promoting cohesion in a critical, constructive and friendly fashion.

Olav Ullaland was not only an outstanding researcher, but also a unique human being who left a deep impression on all those with whom he came into contact. We will never forget him.

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Arnau Brossa Gonzalo, a postdoctoral researcher at the Galician Institute of High Energy Physics (IGFAE) working on the LHCb experiment, died in Santiago on 21 July 2024 following complications from a climbing accident.

Arnau obtained his degree in physics at the University of Barcelona in 2016, specialising in theoretical physics. He continued there for his master’s in astrophysics, particle physics and cosmology, with a thesis on the LHCb experiment.

In 2017 he embarked on his PhD studies in particle physics at the University of Warwick. His thesis, entitled “First observation of B⁰ → D^*(2007)⁰K⁺π^– and B⁰_s → D^*(2007)⁰K^–π⁺ decays in LHCb”, won the Springer Thesis Prize for outstanding PhD research. This was the first LHCb measurement of B decays involving fully reconstructed neutral D^*mesons, which are particularly challenging due to the soft neutral particles emitted in the D^* → Dπ⁰ and D^* → Dγ decays. These modes are nonetheless extremely important to understand as they are backgrounds to a wide range of other studies, including those used for precision measurements of the CKM angle γ.

Following the completion of his PhD, Arnau joined the LHCb group at IGFAE in 2022 to work further on the LHCb experiment, first as a postdoctoral researcher and later as a Juan de la Cierva researcher. He then joined the lepton-flavour-universality group at IGFAE, taking on a leading role in the measurement of the ratios of semileptonic-decay branching fractions to final states with tau leptons relative to muons, denoted R(D) and R(D^*). Arnau had rapidly established himself as an expert in this area, and in early 2024 he had taken on convenership of the LHCb subgroup that was dedicated to this and to similar charged-current lepton-flavour-universality tests.

Arnau’s warmth, kindness, dedication, intelligence and competence will be deeply missed by his many friends at the institute in Santiago and in the LHCb collaboration.

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Robert Aymar was educated at Ecole Polytechnique in Paris. He started his career in plasma physics at Commissariat à l’Energie Atomique (CEA), since renamed Commissariat à l’Energie Atomique et aux Energies Alternatives, at the time when thermonuclear fusion was declassified and research started on its application to energy production. After being involved in several studies at CEA, Aymar contributed to the design of the Joint European Torus, the European tokamak project based on conventional magnet technology, built in Culham, UK in the late 1970s. In the same period, CEA was considering a compact tokamak project based on superconducting magnet technology, for which Aymar decided to use pressurised superfluid helium cooling — a technology then recently developed by Gérard Claudet and his team at CEA Grenoble. Aymar was naturally appointed head of the TORE SUPRA tokamak project, built at CEA Cadarache from 1977 to 1988. The successful project served inter alia as an industrial-size demonstrator of superfluid helium cryogenics, which became a key technology of the LHC.

Robert Aymar set out to bring together the physics of the infinitely large and the infinitely small

As head of the Département des Sciences de la Matière at CEA from 1990 to 1994, Robert Aymar set out to bring together the physics of the infinitely large and the infinitely small, as well as the associated instrumentation, in a department that has now become the Institut de Recherche sur les Lois Fondamentales de l’Univers. In that position, he actively supported CEA-CERN collaboration agreements on R&D for the LHC and served on many national and international committees. In 1993 he chaired the LHC external review committee, whose recommendation proved decisive in the project’s approval. From 1994 to 2003, he led the ITER engineering design activities under the auspices of the International Atomic Energy Agency, establishing the basic design and validity of the project that would be approved for construction in 2006. In 2001, the CERN Council called on his expertise once again by entrusting him to chair the external review committee for CERN’s activities.

When Robert Aymar took over as Director General of CERN in 2004, the construction of the LHC was well under way. But there were many industrial and financial challenges, and a few production crises still to overcome. During his tenure, which saw the ramp-up, series production and installation of major components, the machine was completed and the first beams circulated. That first start-up in 2008 was followed by a major technical problem that led to a shutdown lasting several months. But the LHC had demonstrated that it could run, and in 2009 the machine was successfully restarted. Robert Aymar’s term of office also saw a simplification of CERN’s structure and procedures, aimed at making the laboratory more efficient. He also set about reducing costs and secured additional funding to complete the construction and optimise the operation of the LHC. After retirement, he remained active as scientific advisor to the head of the CEA, occasionally visiting CERN and the ITER construction site in Cadarache.

Robert Aymar was a dedicated and demanding leader, with a strong drive and search for pragmatic solutions in the activities he undertook or supervised. CERN and the LHC project own much to his efforts. He was also a man of culture with a marked interest in history. It was a privilege to serve under his direction.

The post Robert Aymar 1936-2024 appeared first on CERN Courier.

In January 1962, CERN was for the first time moving from machine construction to scientific research with the machines. Director-General Victor Weisskopf took up the pen in the first CERN Courier after a brief hiatus. “This institution is remarkable in two ways,” he wrote. “It is a place where the most fantastic experiments are carried out. It is a place where international co-operation actually exists.”

A new generation of early-career researchers (ECRs) shares his convictions. Now, as then, they do much of the heavy lifting that builds the future of the field. Now, as then, they need resilience and vision. As Weisskopf wrote in these pages, the everyday work of high-energy physics (HEP) can hide its real importance – its romantic glory, as the renowned theorist put it. “All our work is for an idealistic aim, for pure science without commercial or any other interests. Our effort is a symbol of what science really means.”

As CERN turns 70, the Courier now hands the pen to the field’s next generation of leaders. All are new post-docs. Each has already made a tangible contribution and earned recognition from their colleagues. All, in short, are among the most recent winners of the four big LHC collaborations’ thesis prizes. Each was offered carte blanche to write about a subject of their choosing, which they believe will be strategically crucial to the future of the field. Almost all responded. These are their viewpoints.

Invest in accelerator innovation

I come from Dallas, Texas, so the Superconducting Super Collider should have been in my backyard as I was growing up. By the late 1990s, its 87 km ring could have delivered 20 TeV per proton beam. The Future Circular Collider could deliver 50 TeV per proton beam in a 91 km ring by the 2070s. I’d be retired before first collisions. Clearly, we need an intermediate-term project to keep expertise in our community. Among the options proposed so far, I’m most excited by linear electron–positron colliders, as they would offer sufficient energy to study the Higgs self-coupling via di-Higgs production. This could be decisive in understanding electroweak symmetry breaking and unveiling possible Higgs portals.

A paradigm shift for accelerators might achieve our physics goals without a collider’s cost scaling with its energy. A strong investment in collider R&D could therefore offer hope for my generation of scientists to push back the energy frontier. Muon colliders avoid synchrotron radiation. Plasma wakefields offer a 100-fold increase in electric field gradient. Though both represent enormous challenges, psychologists have noted an “end of history” phenomenon, whereby as humans we appreciate how much we have changed in the past, but under­estimate how much we will change in the future. Reflecting on the past physics breakthroughs galvanises me to optimism: unlocking the next chapter of physics has always been within the reach of technological innovation. CERN has been a mecca for accelerator applications in the last 70 years. I’d argue that a strong increase in support for novel collider R&D is the best way to carry this legacy forwards.

Nicole Hartman is a post-doc at the Technical University of Munich and Origins Data Science Lab. She was awarded a PhD by Stanford University for her thesis “A search for non-resonant HH → 4b at √s = 13 TeV with the ATLAS detector – or – 2b, and then another 2b… now that’s the thesis question”.

Reward technical work with career opportunities

This job is a passion and a privilege, and ECRs devote nights and weekends to our research. But this energy should be handled in a more productive way. In particular, technical work on hardware and software is not valued and rewarded as it should be. ECRs who focus on technical aspects are often forced to divide their focus with theoretical work and data analysis, or suffer reduced opportunities to pursue an academic career. Is this correct? Why shouldn’t technical and scientific work be valued in the same way?

I am very hopeful for the future. In recent years, I have seen improvements in this direction, with many supervisors increasingly pushing their students towards technical work. I expect senior leadership to make organisational adjustments to reward and value these two aspects of research in exactly the same way. This cultural shift would greatly benefit our physics community by more efficiently transforming the enthusiasm and hard work of ECRs into skilled contributions to the field that are sustained over the decades.

Alessandro Scarabotto is a postdoctoral researcher at Technische Universität Dortmund. He was awarded a PhD by Sorbonne Université, Paris, for his thesis “Search for rare four-body charm decays with electrons in the final state and long track reconstruction for the LHCb trigger”.

A revolving door to industry

Big companies’ energy usage is currently skyrocketing to fuel their artificial intelligence (AI) systems. There is a clear business adaptation of my research on fast, energy-saving AI triggers, but I feel completely unable to make this happen. Why, as a field, are we unable to transfer our research to industry in an effective way?

While there are obvious milestones for taking data to publication, there is no equivalent for starting a business or getting our research into major industry players. Our collaborations are incubators for ideas and people. They should implement dedicated strategies to help ECRs obtain the funding, professional connections and business skills they need to get their ideas into the wider world. We should be presenting at industry conferences – both to offer solutions to industry and to obtain them for our own research – and industry sessions within our own conferences could bring links to every part of our field.

Most importantly, the field should encourage a revolving door between academia and industry to optimise the transfer of knowledge and skills. Unfortunately, when physicists leave for industry, slow, single-track physics career progressions and our focus on publication count rather than skills make a return unrealistic. There also needs to be a way of attracting talent from industry into physics without the requirement of a PhD so that experienced people can start or return to research in high-profile positions suitable for their level of work and life experience.

Christopher Brown is a CERN fellow working on next-generation triggers. He was awarded a PhD by Imperial College London for his thesis “Fast machine learning in the CMS Level-1 trigger for the High-Luminosity LHC”.

Collaboration, retention and support

I feel a strong sense of agency regarding the future of our field. The upcoming High-Luminosity LHC (HL-LHC) will provide a wealth of data beyond what the LHC has offered, and we should be extremely excited about the increased discovery potential. Looking further ahead, I share the vision of a future Higgs factory as the next logical step for the field. The proposed Future Circular Collider is currently the most feasible option. However, the high cost and evolving geopolitical landscape are causes for concern. One of the greatest challenges we face is retaining talent and expertise. In the US, it has become increasingly difficult for researchers to find permanent positions after completing postdocs, leading to a loss of valuable technical and operational expertise. On a positive note, our field has made significant strides in providing opportunities for students from under­represented nationalities and socioeconomic backgrounds – I am a beneficiary of these efforts. Still, I believe we should intensify our focus on supporting individuals as they transition through different career stages to ensure a vibrant and diverse future workforce.

Prajita Bhattarai is a research associate at SLAC National Accelerator Laboratory in the US. She was awarded her PhD by Brandeis University in the US for her thesis “Standard Model electroweak precision measurements with two Z bosons and two jets in ATLAS”.

Redesign collaborations for equitable opportunity

Particle physics and cosmology capture the attention of nearly every inquisitive child. Though large collaborations and expensive machines have produced some of humankind’s most spectacular achievements, they have also made the field inaccessible to many young students. Making a meaningful contribution is contingent upon being associated with an institution or university that is a member of an experimental collaboration. One typically also has to study in a country that has a cooperation agreement with an international organisation like CERN.

If future experiments want to attract diverse talent, they should consider new collaborative models that allow participation irrespective of a person’s institution or country of origin. Scientific and financial responsibilities could be defined based on expertise and the research grants of individual research groups. Remote operations centres across the globe, such as those trialled by CERN experiments, could enable participants to fulfil their responsibilities without being constrained by international borders and travel budgets; the worldwide revolution in connectivity infrastructure could provide an opportunity to make this the norm rather than the exception. These measures could provide equitable opportunities to everyone while simultaneously maximising the scientific output of our field.

Spandan Mondal is a postdoctoral fellow at Brown University in the US. He was awarded a PhD by RWTH Aachen in Germany for his thesis on the CMS experiment “Charming decays of the Higgs, Z, and W bosons: development and deployment of a new calibration method for charm jet identification”.

Reward risk taking

Young scientists often navigate complex career paths, where the pressure to produce consistent publishable results can stifle creativity and discourage risk taking. Traditionally, young researchers are evaluated almost solely on achieved results, often leading to a culture of risk aversion. To foster a culture of innovation we must shift our approach to research and evaluation. To encourage bold and innovative thinking among ECRs, the fuel of scientific progress, we need to broaden our definition of success. European funding and grants have made strides in recognising innovative ideas, but more is needed. Mentorship and peer-review systems must also evolve, creating an environment open to innovative thinking, with a calculated approach to risk, guided by experienced scientists. Concrete actions include establishing mentorship programmes during scientific events, such as workshops and conferences. To maximise the impact, these programmes should prioritise diversity among mentors and mentees, ensuring that a wide range of perspectives and experiences are shared. Equally important is recognising and rewarding innovation. This can be achieved by dedicated awards that value originality and potential impact over guaranteed success. Celebrating attempts, even failed ones, can shift the focus from the outcome to the process of discovery, inspiring a new generation of scientists to push the boundaries of knowledge.

Francesca Ercolessi is a post-doc at the University of Bologna. She was awarded a PhD by the University of Bologna for her thesis “The interplay of multiplicity and effective energy for (multi) strange hadron production in pp collisions at the LHC”.

Our employment model stifles creativity

ECR colleagues are deeply passionate about the science they do and wish to pursue a career in our field – “if possible”. Is there anything one can do to better support this new generation of physicists? In my opinion, we have to address the scarcity of permanent positions in our field. Short-term contracts lead to risk aversion, and short-term projects with a high chance of publication increase your employment prospects. This is in direct contrast to what is needed to successfully complete ambitious future projects this century – projects that require innovation and out-of-the-box thinking by bright young minds.

In addition, employment in fundamental science is more than ever in direct competition with permanent jobs in industry. For example, machine learning and computing experts innovate our field with novel analysis techniques, but end up ultimately leaving our field to apply their skills in permanent employment elsewhere. If we want to keep talent in our field we must create a funding structure that allows realistic prospects for long-term employment and commitment to future projects.

Florian Jonas is a postdoctoral scholar at UC Berkeley and LBNL. He was awarded a PhD by the University of Münster for his thesis on the ALICE experiment “Probing the initial state of heavy-ion collisions with isolated prompt photons”.

Embrace private expertise and investment

The two great challenges of our time are data taking and data analysis. Rare processes like the production of Higgs-boson pairs have cross sections 10 orders of magnitude smaller than their backgrounds – and during HL-LHC operation the CMS trigger will have to analyse about 50 TB/s and take decisions with a latency of 12.5 μs. In recent years, we have made big steps forward with machine learning, but our techniques are not always up to speed with the current state-of-the-art in the private sector.

To sustain and accelerate our progress, the HEP community must be more open to new sources of funding, particularly from private investments. Collaborations with tech companies and private investors can provide not only financial support but also access to advanced technologies and expertise. Encouraging CERN–private partnerships can lead to the development of innovative tools and infrastructure, driving the field forward.

The recent establishment of the Next Generation Trigger Project, funded by the Eric and Wendy Schmidt Fund for Strategic Innovation, represents the first step toward this kind of collaboration. Thanks to overlapping R&D interests, this could be scaled up to direct partnerships with companies to introduce large and sustained streams of funds. This would not only push the boundaries of our knowledge but also inspire and support the next generation of physicists, opening new tenured positions thanks to private funding.

Jona Motta is a post-doc at Universität Zürich. He was awarded a PhD by Institut Polytechnique de Paris for his thesis “Development of machine learning based τ trigger algorithms and search for Higgs boson pair production in the bbττ decay channel with the CMS detector at the LHC”.

Stability would stop the brain drain

The proposed Future Circular Collider presents a formidable challenge. Every aspect of its design, construction, commissioning and operations would require extensive R&D to achieve the needed performance and stability, and fully exploit the machine’s potential. The vast experience acquired at the LHC will play a significant role. Knowledge must be preserved and transmitted between generations. But the loss of expertise is already a significant problem at the LHC.

The main reason for young scientists to leave the field is the lack of institutional support: it’s hard to count on a stable working environment, regardless of our expertise and performance. The difficulty in finding permanent academic or research positions and the lack of recognition and advancement are all viewed as serious obstacles to pursuing a career in HEP. In these conditions, a young physicist might find competitive sectors such as industry or finance more appealing given the highly stable future they offer.

It is crucial to address this problem now for the HL-LHC. Large HEP collaborations should be more supportive to ensure better recognition and career advancement towards permanent positions. This kind of policy could help to retain young physicists and ensure they continue to be involved in the current HEP projects that would then define the success of the FCC.

Hassnae El Jarrari is a CERN research fellow in experimental physics. She was awarded a PhD by Université Mohammed-V De Rabat for her thesis “Dark photon searches from Higgs boson and heavy boson decays using pp collisions recorded at √s = 13 TeV with the ATLAS detector at the LHC and performance evaluation of the low gain avalanche detectors for the HL-LHC ATLAS high-granularity timing detector”.

Reduce environmental impacts

The main challenge for the future of large-scale HEP experiments is reducing our environmental impact, and raising awareness is key to this. For example, before running a job, the ALICE computing grid provides an estimate of its CO₂-equivalent carbon footprint, to encourage code optimisation and save power.

I believe that if we want to thrive in the future, we should adopt a new way of doing physics where we think critically about the environment. We should participate in more collaboration meetings and conferences remotely, and promote local conferences that are reachable by train.

I’m not saying that we should ban air travel tout court. It’s especially important for early-career scientists to get their name out there and to establish connections. But by attending just one major international conference in person every two years, and publicising alternative means of communication, we can save resources and travel time, which can be invested in our home institutions. This would also enable scientists from smaller groups with reduced travel budgets to attend more conferences and disseminate their findings.

Luca Quaglia is a postdoctoral fellow at the Istituto Nazionale di Fisica Nucleare, Sezione di Torino. He was awarded his PhD by the University of Torino for his thesis “Development of eco-friendly gas mixtures for resistive plate chambers”.

Invest in software and computing talent

With both computing and human resources in short supply, funds must be invested wisely. While scaling up infrastructure is critical and often seems like the simplest remedy, the human factor is often overlooked. Innovative ideas and efficient software solutions require investment in training and the recruitment of skilled researchers.

This investment must start with a stronger integration of software education into physics degrees. As the boundaries between physics and computer science blur, universities must provide a solid foundation, raise awareness of the importance of software in HEP and physics in general, and promote best practices to equip the next generation for the challenges of the future. Continuous learning must be actively supported, and young researchers must be provided with sufficient resources and appropriate mentoring from experienced colleagues.

Software skills remain in high demand in industry, where financial incentives and better prospects often attract skilled people from academia. It is in the interest of the community to retain top talent by creating more attractive and secure career paths. After all, a continuous drain of talent and knowledge is detrimental to the field, hinders the development of efficient software and computing solutions, and is likely to prove more costly in the long run.

Joshua Beirer is a CERN research fellow in the offline software group of the ATLAS experiment and part of the lab’s strategic R&D programme on technologies for future experiments. He was awarded his PhD by the University of Göttingen for his thesis “Novel approaches to the fast simulation of the ATLAS calorimeter and performance studies of track-assisted reclustered jets for searches for resonant X → SH → bbWW^* production with the ATLAS detector”.

Strengthen international science

HEP is at an exciting yet critical inflection point. The coming years hold both unparalleled opportunities and growing challenges, including an expanding arena of international competition and the persistent issue of funding and resource allocation. In a swiftly evolving digital age, scientists must rededicate themselves to public service, engagement and education, informing diverse communities about the possible technological advancements of HEP research, and sharing with the world the excitement of discovering fundamental knowledge of the universe. Collaborations must be strengthened across international borders and political lines, pooling resources from multiple countries to traverse cultural gaps and open the doors of scientific diplomacy. With ever-increasing expenses and an uncertain political future, scientists must insist upon the importance of public research irrespective of any national agenda, and reinforce scientific veracity in a rapidly evolving world that is challenged by growing misinformation. Most importantly, the community must establish global priorities in a maturing age of precision, elevating not only new discoveries but the necessary scientific repetition to better understand what we discover.

The most difficult issues facing HEP research today are addressable and furthermore offer excellent opportunities to develop the scientific approach for the next several decades. By tackling these issues now, scientists can continue to focus on the mysteries of the universe, driving scientific and technological advancements for the betterment of all.

Ezra D. Lesser is a CERN research fellow working with the LHCb collaboration. He was awarded his PhD in physics by the University of California, Berkeley for his thesis: Measurements of jet substructure in pp and Pb–Pb collisions at √s_NN = 5.02 TeV with ALICE”.

Recognise R&D

ECRs must drive the field’s direction by engaging in prospect studies for future experiments, but dedicating time to this essential work comes at the expense of analysing existing data – a trade-off that can jeopardise our careers. With most ECRs employed on precarious two-to-four year contracts, time spent on these studies can result in fewer high-profile publications, making it harder to secure our next academic position. Another important factor is the unprecedented timescales associated with many prospective futures. Those working on R&D today may never see the fruits of their labour.

Anxieties surrounding these issues are often misinterpreted as disengagement, but nothing could be further from the truth. In my experience, ECRs are passionate about research, bringing fresh perspectives and ideas that are crucial for advancing the field. However, we often struggle with institutional structures that fail to recognise the breadth of our contributions. By addressing longstanding issues surrounding attitudes toward work–life balance and long-term job stability – through measures such as establishing enforced minimum contract durations, as well as providing more transparent and diverse sets of criteria for transitioning to permanent positions – we can create a more supportive environment where HEP thrives, driven by the creativity and innovation of its next generation of leaders.

Savannah Clawson is a postdoctoral fellow at DESY Hamburg. She was awarded her PhD by the University of Manchester for her thesis “The light at the end of the tunnel gets weaker: observation and measurement of photon-induced W⁺W^– production at the ATLAS experiment”.

The post Voices from a new generation appeared first on CERN Courier.

CERN’s experimental and theoretical research laid many of the building blocks of one of the most successful and impactful scientific theories in human history: the Standard Model of particle physics. Its contributions go beyond the best-known discoveries, such as of neutral currents and the seemingly fundamental W, Z and Higgs bosons, which have such far-reaching significance for our universe. I also wish to draw attention to the many dozens of new composite particles at the LHC and the incredibly high-precision agreement between theoretical calculation performed in quantum chromodynamics and the experimental results obtained at the LHC. These amazing discovering were made possible thanks to the many technological innovations made at CERN.

But knowledge creation and accumulation are only half the story. CERN’s human ecosystem is an oasis in which the words “collaboration among peoples for the good of humanity” can be uttered without grandstanding or hypocrisy.

What role does the CERN Council play?

CERN’s member states are each represented by two delegates to the CERN Council. Decisions are made democratically, with equal voting power for each national delegation. According to the convention approved in 1954, and last revised in 1971, Council determines scientific, technical and administrative policy, approves CERN’s programmes of activities, reviews its expenditures and approves the laboratory’s budget. The Director-General and her management team work closely with Council to develop the Organization’s policies, scientific activities and budget. Director-General Fabiola Gianotti and her management team are now collaborating with Council to forge CERN’s future scientific vision.

What’s your vision for CERN’s future?

As CERN Council president, I have a responsibility to be neutral and reflect the collective will of the member states. In early 2022, when I took up the presidency, Council delegates unanimously endorsed my evaluation of their vision: that CERN should continue to offer the world’s best experimental high-energy physics programme using the best technology possible. CERN now needs to successfully complete the High-Luminosity LHC (HL-LHC) project and agree on a future flagship project.

I strongly believe the format of the future flagship project needs to crystallise as soon as possible. As put to me recently in a letter from the ECFA early-career researchers panel: “While the HL-LHC constitutes a much-anticipated and necessary advance in the LHC programme, a clear path beyond it for our future in the field must be cemented with as little delay as possible.” It can be daunting for young people to speak out on strategy and the future of the field, given the career insecurities they face. I am very encouraged by their willingness to put out a statement calling for immediate action.

At its March 2024 session, Council agreed to ignite the process of selecting the next flagship project by going ahead with the fourth European Strategy for Particle Physics update. The strategy group are charged, among other things, with recommending what this flagship project should be to Council. As I laid down the gavel concluding the meeting I looked around and sensed genuine excitement in the Chambers – that of a passenger ship leaving port. Each passenger has their own vision for the future. Each is looking forward to seeing what the final destination will look like. Several big pieces had started falling into place, allowing us to turn on the engine.

What are these big pieces?

Acting upon the recommendation of the 2020 update of the European Strategy for Particle Physics, CERN in 2021 launched a technical and financial feasibility study for a Future Circular Collider (FCC) operating first as a Higgs, electroweak and top factory, with an eye to succeeding it with a high-energy proton–proton collider. The report will include the physics motivation, technological and geological feasibility, territorial implementation, financial aspects, and the environmental and sustainability challenges that are deeply important to CERN’s member states and the diverse communes of our host countries.

It is also important to add that CERN has also invested, and continues to invest, in R&D for alternatives to FCC such as CLIC and the muon collider. CLIC is a mature design, developed over decades, which has already precipitated numerous impactful societal applications in industry and medicine; and to the best of my knowledge, at present no laboratory has invested as much as CERN in muon-collider R&D.

A mid-term report of FCC’s feasibility study was submitted to subordinate bodies to the CERN management mid-2023, and their resulting reports were presented to CERN’s finance and scientific-policy committees. Council received the outcomes with great appreciation for the work involved during an extraordinary session on 2 February, and looks forward to the completion of the feasibility study in March 2025. Timing the European strategy update to follow hot on its heels and use it as an input was the natural next step.

At the June Council session, we started dealing with the nitty gritty of the process. A secretariat for the European Strategy Group was established under the chairmanship of Karl Jakobs, and committees are being appointed. By January 2026 the Council could have at its disposal a large part of the knowledge needed to chart the future of the CERN vision.

How would you encourage early-career researchers (ECRs) to engage with the strategy process?

ECRs have a central role to play. One of the biggest challenges when attempting to build a major novel research infrastructure such as the proposed FCC – which I sometimes think of as a frontier circular collider – is to maintain high-quality expertise, enthusiasm and optimism for long periods in the face of what seem like insurmountable hurdles. Historically, the physicists who brought a new machine to fruition knew that they would get a chance to work on the data it produced or at least have a claim for credit for their efforts. This is not the case now. Success rests on the enthusiasm of those who are at the beginning of their careers today just as much as senior researchers. I hope ECRs will rise to the challenge and find ways to participate in the coming European Strategy Group-sponsored deliberations and become future leaders of the field. One way to engage is to participate in ECR-only strategy sessions like those held at the yearly FCC weeks. I’d also encourage other countries to join the UK in organising nationwide ECR-only forums for debating the future of the field, such as I initiated in Birmingham in 2022.

What’s the outlook for collaboration and competition between CERN and other regions on the future collider programme?

Over decades, CERN has managed to place itself as the leading example of true international scientific collaboration. For example, by far the largest national contingent of CERN users hails from the US. Estonia has completed the process of joining CERN as a new member state and Brazil has just become the first American associate member state. There is a global agreement among scientists in China, Europe, Japan and the US that the next collider should be an electron–positron Higgs factory, able to study the properties of the Higgs boson with high precision. I hope that – patiently, and step by step – ever more global integration will form.

Do member states receive a strong return on their investment in CERN?

Research suggests that fundamental exploration actively stimulates the economy, and more than pays for itself. Member states and associate member states have steadfastly supported CERN to the tune of CHF 53 billion (unadjusted for inflation) since 1954. They do this because their citizens take pride that their nation stands with fellow member states at the forefront of scientific excellence in the fundamental exploration of our universe. They also do this because they know that scientific excellence stimulates their economies through industrial innovation and the waves of highly skilled engineers, entrepreneurs and scientists who return home trained, inspired and better connected after interacting with CERN.

A bipartisan US report from 2005 called “Rising above the gathering storm” offered particular clarity, in my opinion. It asserted that investments in science and technology benefit the world’s economy, and it noted both the abruptness with which a lead in science and technology can be lost and the difficulty of recovering such a lead. One should not be shy to say that when CERN was established in 1954, it was part of a rather crowded third place in the field of experimental particle physics, with the Soviet Union and the United States at the fore. In 2024, CERN is the leader of the field – and with leadership comes a heavy responsibility to chart a path beneficial to a large community across the whole planet. As CERN Council president, I thank member states for their steadfast support and I applaud them for their economic and scientific foresight over the past seven decades. I hope it will persist long into the 21st century.

Is there a role for private funding for fundamental research?

In Europe, substantial private-sector support for knowledge creation and creativity dates back at least to the Medici. Though it is arguably less emphasised in our times, it plays an important role today in the US, the UK and Israel. Academic freedom is a sine qua non for worthwhile research. Within this limit, I don’t believe there is any serious controversy in Council on this matter. My sense is that Council fully supports the clear division between recognising generosity and keeping full academic and governance freedom.

What challenges has Council faced during your tenure as president?

In February 2022, the Russian Federation, an observer state, invaded Ukraine, which has been an associate member state since 2016. This was a situation with no precedent for Council. The shape of our decisions evolved for well over a year. Council members decided to cover from their own budgets the share of Ukraine’s contribution to CERN. Council also tried to address as much as possible the human issues resulting from the situation. It decided to suspend the observer status in the Council of the Russian Federation and the Joint Institute for Nuclear Research. Council also decided to not extend its International Collaboration Agreements with the Republic of Belarus and the Russian Federation. CERN departments also undertook initiatives to support the Ukrainian scientific community at CERN and in Ukraine.

A second major challenge was to mitigate the financial pressures being experienced around the world, such as inflation and rising costs for energy and materials. A package deal was agreed upon in Council that included significant contributions from the member states, a contribution from the CERN staff, and substantial savings from across CERN’s activities. So far, these measures seem to have addressed the issue.

I thank member states for their steadfast support and I applaud them for their economic and scientific foresight over the past seven decades

While these key challenges were tackled, management worked relentlessly on preparing an exhaustive FCC feasibility study, to ensure that CERN stays on course in developing its scientific and technological vision for the field of experimental high-energy physics.

The supportive reaction of Council to these challenges demonstrated its ability to stay on course during rough seas and strong side winds. This cohesion is very encouraging for me. Time and again, Council faced difficult decisions in recent years. Though convergence seemed difficult at first, thanks to a united will and the help of all Council members, a way forward emerged and decisions were taken. It’s important to bear in mind that no matter which flagship project CERN embarks on, it will be a project of another order of magnitude. Some of the methods that made the LHC such a success can continue to accompany us, some will need to evolve significantly, and some new ones will need to be created.

Has the ideal of Science for Peace been damaged?

Over the years CERN has developed the skills needed to construct bridges. CERN does not have much experience in dismantling bridges. This issue was very much on the mind of Council as it took its decisions.

Do you wish to make some unofficial personal remarks?

Thanks. Yes. I would like to mention several things I feel grateful for.

Nobody owes humanity a concise description of the laws of physics and the basic constituents of matter. I am grateful for being in an era where it seems possible, thanks to a large extent to the experiments performed at CERN. Scientists from innumerable countries, who can’t even form a consensus on the best 1970s rock band, have succeeded time and again to assemble the most sophisticated pieces of equipment, with each part built in a different country. And it works. I stand in awe in front of that.

The ecosystem of CERN, the experimental groups working at CERN and the CERN Council are how I dreamt as a child that the United Nations would work. The challenges facing humanity in the coming centuries are formidable. They require international collaboration among the best minds from all over the planet. CERN shows that this is possible. But it requires hard work to maintain this environment. Over the years serious challenges have presented themselves, and one should not take this situation for granted. We need to be vigilant to keep this precious space – the precious gift of CERN.

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Ilario Boscolo, who was one of the proponents of the AEgIS experiment at CERN, passed away on 16 April 2024 at the age of 84.

Ilario Boscolo was born in Codevigo, Italy in 1940 and graduated from the nearby University of Padua. In 1968 he joined the University of Lecce, where he initiated research in accelerator physics, high-intensity electron beams and free electron lasers (FELs), and far-infrared and CO₂ lasers. Among his important scientific contributions at that time were the development of a prototype electrostatic accelerator, investigations on far-infrared lasers optically pumped in a cavity, and a much-cited theoretical proposal for a two-stage FEL for coherent harmonic amplification (an optical klystron). Ilario spent long periods of study in international research institutes, including the ENEA fusion energy centre in Frascati and the University of California Santa Barbara, where he collaborated with world-leading FEL researchers Luis Elias and William Colson.

In 1987 Ilario was called to the University of Milan, where he became full professor, to participate in the INFN project ELFA (electron laser facility for acceleration) and was responsible for the photocathode emission. His interest then turned to other topics, including efficient electron sources based on field emission from carbon nanotubes or ferroelectric ceramics and, within CERN, pulsed laser phase coding systems for new acceleration facilities. Within the INFN SPARC–SPARX initiative, started in 2003 and based in Frascati, he focused on laser applications for the development of pulsed, high-brightness UV and X-ray FEL sources. In particular, he showed that the high beam quality of the electron sources depends on suitable shaping of comb laser pulses, the study of which was realised in a dedicated laser laboratory at Milan founded by Ilario.

In 2007 Ilario was one of the proponents of the AEgIS experiment at the CERN Anti­proton Decelerator, which aimed to investigate the properties of antimatter, in particular its gravitational interactions. This required the production of a low-energy beam of antihydrogen atoms, obtained by a charge-exchange process with positronium atoms laser-excited at Rydberg levels. Led by Ilario, the Milan laser laboratory was responsible for the laser system that was required to make this pairing possible. AEgIS demonstrated the first pulsed-production of antihydrogen atoms in 2018, enabling a series of antimatter studies that are ongoing.

In all his activities, Ilario showed great passion and enthusiasm for both science and its applications. This positive attitude was also widely displayed through his didactical activity in various courses at the University of Milan. He was responsible for a new physics laboratory for the biology programme and for the laser laboratory for the physics programme. In addition, his greatest success was the complete reconstruction of the general physics laboratory for first-year students. By encouraging students to practice and elaborate on their own, with only little guidance from the teacher, this laboratory left an indelible mark on their training as physicists.

Another strong passion of Ilario was civil commitment, reflected in his constant engagement with university governance and studies of politics and economics, to which he dedicated himself with his usual inexhaustible enthusiasm, particularly after his retirement.

Ilario is remembered by his collaborators and students as a person of great culture, of brilliant insights, of a willingness to discuss physics and politics with anyone, and as an exquisite friend. He was a true scientist, leaving a deep mark on physics and a bright memory for everyone who had the honour of knowing him.

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Born in Hatfield, to the north of London, in 1928, Alec graduated in physics from Imperial College London in 1949. He continued there for his PhD, building a Van de Graaff accelerator to study (p, alpha) reactions in light nuclei. Yes, in those days postgraduate students built their own accelerators! One of his older fellow students was Don Perkins, who passed away in 2022.

In 1952 Alec interrupted his studies to take a job in the publicity department of General Electric at its site in Kent, England. Nine years later he came to CERN to take over the editorship of CERN Courier from Roger Anthoine. The Courier was then just two years old, and it was during Alec’s period as editor that it began to move beyond its initial role as the house journal for CERN staff to one that communicated the work of CERN and other laboratories to a wider scientific and technical readership. Marking the end of Alec’s editorship in the December 1965 issue, Anthoine wrote: “The editing and production of our periodical, with limited means, requires not only very definite intellectual qualities, for collecting and processing information from all over the Laboratory, but also considerable physical and moral toughness to cope with the many dictates of production, which are the lot of every editor… It is mainly thanks to [Alec’s] drive that CERN Courier, which now has a circulation of 6000 copies (French and English versions combined), has risen from the rank of ‘internal information journal’ to that of ‘world spokesman for European sub-nuclear physics’.”

In 1966 Alec moved to the CERN scientific information service as the physics subject specialist, remaining there until his retirement in February 1993. His accurate and painstaking work developing the library’s bibliographic databases provided the nucleus for those searchable on the CERN Document Server today.

Alec leaves behind Annemarie, his wife for over 70 years, his daughters Barbara and Dagmar, and his four grandchildren.

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Renowned experimental physicist and co-initiator of relativistic heavy-ion physics, Rudolf Bock, passed away on 9 April 2024 aged 96.

Rudolf Bock was born in Mannheim, Germany in May 1927 and obtained his diploma in physics from the University of Heidelberg in 1954. He conducted his doctoral thesis on deuteron-induced nuclear reactions at the cyclotron of the Max Planck Institute for Medical Research in Heidelberg and received his doctorate from Heidelberg University in 1958. He then investigated nuclear reactions at the newly founded MPI for Nuclear Physics (MPIK) at the tandem accelerators there, initially with light ions and from 1963 with heavier ions.

In 1967 he was appointed full professor at the University of Marburg and was involved in the development of a joint accelerator project for heavy-ion research, ultimately leading to the UNILAC accelerator project. On 17 December 1969, the research centre GSI (Gesellschaft für Schwerionenforschung) was founded in Darmstadt–Wixhausen. As one of its founding fathers and subsequently as a long-standing member of the GSI board of directors, Rudolf Bock played a decisive role in the development of nuclear physics with heavy ions. At the same time, he maintained his contacts with Heidelberg as an honorary professor and as an external scientific member of the MPIK. In 2000 he was awarded an honorary doctorate from Goethe University Frankfurt.

Research with relativistic heavy-ion beams soon led to great successes. From 1974 Rudolf Bock established a working group at GSI under the leadership of Hans Gutbrod and Reinhard Stock, who set up and successfully carried out two major experiments at the Berkeley Bevalac accelerator. These resulted in the discovery of compressed, hot nuclear matter with hydrodynamic flow behaviour and thus formed the basis for his later experiments on quark–gluon plasma at CERN.

From the mid-1980s, the heavy-ion synchrotron SIS18 was set up at GSI under the leadership of director Paul Kienle. Thanks to Rudolf Bock’s guidance and in cooperation with surrounding universities, three new experiments (FOPI, KAOS and TAPS) were created, which focused on the formation of compressed nuclear matter as well as on hadron production and in particular the formation of light atomic nuclei. Around the same time, he was working on plans for experiments at much higher energies, which could ultimately only be realised at the CERN
SPS accelerator, with decisive contributions from GSI and LBL Berkeley. This led to the development of today’s global programme in ultra-relativistic nuclear–nuclear collisions, which has been pursued since the 1990s at the AGS and SPS, from 2000 with four experiments at RHIC and, since 2010, has been led by ALICE at the LHC at the highest energies.

The cooperation between GSI and LBL Berkeley was not only the beginning of relativistic heavy-ion physics. Supported by Hermann Grunder, then head of the LBL accelerator department, Rudolf Bock started the inertial confinement fusion programme in Germany. He also laid an important foundation for ion-beam therapy by supporting the secondment of Gerhard Kraft from GSI to the cancer-therapy programme at LBL. After his retirement in December 1995, Rudolf Bock maintained his scientific activities at GSI, his primary interest being the development of experiments on plasma physics and inertial-confinement fusion with high-intensity ion and laser beams.

Throughout the course of his scientific career, Rudolf Bock established numerous new research collaborations with institutes in Germany and abroad. As he himself had taken part in the Second World War and had spent several years as a prisoner of war in Russia, the idea of international understanding and peacekeeping was an important concern for him. As early as 1969 he invited many Russian scientists to the nuclear-physics conference at MPIK, and from the 1970s he promoted many collaborations between GSI and Russian institutes. He also pushed for Russia to become the largest member state in the GSI/FAIR project. The Russian invasion of Ukraine in February 2022 was therefore a great disappointment for him and for all of us.

Rudolf Bock was regularly present at GSI until his last days and continued to take an interest in current research and developments on campus. His advice and foresight will be sorely missed.

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Theoretical physicist Werner Rühl died on 31 December 2023 in Füssen, Germany at the age of 86.

He was born in 1937, at a time when theoretical physics in Germany was being destroyed by the Nazis. After the Second World War, the ongoing study of cosmic rays and the availability of higher energies from accelerators made particle physics the most interesting field for budding researchers like him. Part of the way ahead was obvious: learn from the US and profit from the new spirit of European unity embodied by the creation of CERN.

Rühl followed this path in the straightest possible way. He obtained his PhD in 1962 in Cologne and became a research associate at CERN in 1964. Two years later he took up a postdoc at Rockefeller University, New York, before returning to CERN as a staff member in 1967, and obtained a chair in 1970 at the newly founded University of Kaiserslautern.

A more difficult decision concerned mathematics, for which many experimentalists had little regard. Initially, Einstein had shared this attitude, but then he worked hard on Riemannian geometry to understand gravity. Heisenberg’s successes were based on deep mathematics, too, but he tried his best to limit its scope. SU(2) and the analogy between spin and isospin were fundamental, and the representation theory of SU(2) had been fully explored in the context of atomic physics. Dirac’s understanding of spinors and his introduction of the delta distribution opened the way for a thorough investigation of non-compact groups like SL(2,C). This allowed us to break the wall between maths and physics, which happened initially in the Soviet Union. Rühl was very aware of this fact and was deeply impressed by the work of Israel Moiseevich Gelfand. In winter 1967/1968 he gave a series of lectures on this topic for the academic training programme at CERN, which in 1970 became the core of his book The Lorentz group and harmonic analysis. A mathematical fruit was his elementary proof of the Plancherel theorem for classical groups, published in 1969.

Rühl’s appointment to a chair at Kaiserslautern was a happy choice for both sides. Internationally recognised professors like Rühl had adequate resources for students, visitors and conferences, and four theory colleagues were hired between 1970 and 1973. In 1983–1985 Rühl was chairman of the physics department and member of the university senate. He published good papers with his PhD students and supported the global development of science, in particular through his work with postdocs from Oran University. For many years he also worked as a mentor for gifted students from all faculties for the prestigious Studienstiftung des deutschen Volkes scholarship foundation.

Despite his dominating affinity for mathematics, Rühl maintained an interest in experimental physics and occasionally published related work. His understanding of Russia facilitated successful collaborations with outstanding colleagues who had moved to the West, with some of his most important contributions stemming from his collaborations with colleagues from Yerevan. After his retirement in 2004 he continued to publish as before. Eleven years later he moved to Füssen near the Alps. For five years he could enjoy his passion for skiing, before an accident impaired his health.

Werner Rühl always had an open mind for new developments. He had studied the large-N behaviour of theories with symmetries like O(N) and did respected work on lattice theories. From the 1980s, his citation rate increased more and more – a tendency that lasted way beyond his retirement. The original take on AdS/CFT duality in the context of O(N) sigma models and high-spin theories stands out the most. At the end of his life it must have been a great satisfaction for Werner Rühl to watch the ripening of these late fruits.

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Atsuhiko began his research at the Tokyo Institute of Technology, initially focusing on large-area avalanche photodiodes as fast photon and soft X-ray detectors. In 1998 he defended his PhD thesis “Study of Micro Strip Gas Chamber as a Time-Resolved X-ray Area Detector”, earning the second High Energy Physics Young Researcher’s Award from the Japan Association of High Energy Physicists. In 2000, alongside Toru Tanimori, he introduced the micro pixel chamber (micro-PIC), a new gaseous detector for X-ray, gamma-ray and charged-particle imaging. It was fully developed using printed circuit board technology and free of floating structures like wires, mesh or foils, featuring a pin-shaped anode surrounded by a ring-shaped cathode.

In 2001 Atsuhiko moved to Kobe University, where he joined the ATLAS experiment and devoted his efforts to commissioning the ATLAS thin gap chambers (TGCs). He was also in charge of integrating the front-end electronics on the KEK TGC detectors and of detector quality assurance and control. Later, at CERN, he led the acceptance quality control of the ATLAS TGCs.

Atsuhiko could always merge his love for experiments with a passion for new ideas. “We need new ‘eyes’ to catch a glimpse of science’s frontier”, he once said. Along with his group in Kobe, while making significant contributions in ATLAS to the design and construction of the new large resistive micromegas for the Muon New Small Wheel, he conducted R&D on the use of sputtered layers of diamond-like carbon (DLC) as resistive elements to quench discharges and played a crucial role in connecting with Japanese industry. He was among the first to test the technology with micromegas, apply it to the micro-PIC detector, and pioneer its use as electrodes for the novel resistive plate chambers he proposed for the MEG II experiment. He supported the use of DLC in the final TPC micromegas of the near detectors of the T2K experiment while serving as a liaison person with BE-Sput in Kyoto. DLC is now the predominant approach in most new resistive MPGD detectors.

In his research, Atsuhiko always placed great emphasis on mentoring students and giving them access to a worldwide community of experts, facilities and experiments. He meticulously shared all relevant research conducted by Japanese colleagues, ensuring proper visibility and recognition for his community. This has been crucial in the international RD51 collaboration on MPGD technologies, within which he played a significant role in its formation and management. During the transition from the MPGD-based RD51 collaboration to the upcoming DRD1, which encompasses a broader scope of technologies and applications, Atsuhiko made a crucial contribution by maintaining strong ties with the Asian community.

Atsuhiko’s vibrant enthusiasm and infectious smile leave an irreplaceable void. His departure is a profound loss, leaving behind a loving wife and two children.

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Within CERN circles, Armin Hermann is mainly known as one of the co-editors of the authoritative History of CERN volumes covering the period from the beginnings of the Organization up to 1965. But he did so much more in the field of the history of science.

Armin Hermann was born on 17 June 1933 in Vernon, British Columbia, Canada and grew up in Upper Bavaria in Germany. He studied physics at Ludwig Maximilian University in Munich and obtained his doctorate in theoretical physics in 1963 with a dissertation on the “Mott effect for elementary particles and nuclei of electromagnetic structure”. He worked for a few years at DESY and performed synchrotron-oscillation calculations with an IBM 650 computer. Subsequently, Hermann decided to change his focus from physics proper to its history, which had preoccupied him since his student days.

Hermann was the first to occupy a chair in the history of science and technology at the University of Stuttgart – a chair not situated either at a science or mathematics faculty but rather among general historians. During his 30 year-long tenure, he authored important monographs on quantum theory, quantum mechanics and elementary particle theory. He wrote books on the history of atomic physics titled Weltreich der Physik: Von Galilei bis Heisenberg, The New Physics: The Route into the Atomic Age, and How Science Lost its Innocence, alongside numerous biographies (including Planck, Heisenberg, Einstein and Wirtz) and historical studies on companies, notably on the German optics firm Carl Zeiss. All became very popular among the physics community.

Meanwhile at CERN, the attitude among physicists towards studies in the history of science was rather negative – the mantra was “We don’t care of history, we make history”. However, in 1980, the advisory committee for the CERN History Project examined a feasibility study conducted by Hermann and decided to establish a European study team to write the history of CERN from its early beginnings until at least 1963, with an overview of later years. The project was to be completed within five years and financed outside the CERN budget. Hermann was asked by CERN Council to assume responsibility for the project, and from 1982 to 1985 he was freed from teaching obligations in Stuttgart to conduct research at CERN. He became co-editor of first two volumes on the history of CERN: Launching the European Organization for Nuclear Research and Building and Running the Laboratory, 1954–1965. A third volume covering the story of the history of CERN from the mid-1960s to the late 1970s later appeared under the editorship of John Krige in 1996.

Armin passed away in February 2024 in his home in Oberstarz near Miesbach, nestled among the alpine hills, which he had always felt attached to and which was also the main reason why he declined several tempting calls to other renowned universities. His wife Steffi, his companion of many decades, was by his side to the very end. Many historians of physics, science and technology in Germany and abroad mourn the loss of this influential pioneer in the history of science.

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Expanding universes

The book starts with an exhaustive journey through the history of cosmology. It reviews the ancient idea of an eternal mathematical universe, passes through the ages of Copernicus and Newton, and then enters the modern era of Einstein’s universe. Hertog thoroughly explores static and expanding universes, Hoyle’s steady-state cosmos, Hartle and Hawking’s no-boundary universe, Guth’s inflationary universe and Linde’s multiverse with eternal inflation. Everything culminates in the proposal for holographic quantum cosmology that the author developed together with the late Hawking.

What makes the book especially interesting is its philosophical reflections on the historical evolution of various underlying scientific paradigms. For example, the old Greeks developed the Platonic view that the workings of the world should be governed by eternal mathematical laws. This laid the groundwork for the reductionistic worldview that many scientists – especially particle physicists – subscribe to today.

Hertog argues that this way of thinking is flawed, especially when confronted with a Big Bang followed by a burst of inflation. Given the supremely fine-tuned structure of our universe, as is necessitated by the existence of atoms, galaxies and ultimately us, how could the universe “know” back at the time of the Big Bang that this fine-tuned world would emerge after inflation and phase transitions?

The quest to scientifically understand this apparent intelligent design has led to physical scenarios such as eternal inflation, which produces an infinite collection of pocket universes with their own laws. These ideas blend the anthropic principle – that only a life-friendly universe can be observed – into the narrative of a multiverse.

However, for anthropic reasoning to make sense, one needs to specify what a typical observer would be, observes Hertog, because otherwise the statement is circular. Instead, he argues that one should interpret the history of the universe as an evolutionary process. Not only would physical objects continuously evolve, but also the laws that govern them, thereby building up an enormous chain of frozen accidents analogous to the evolutionary tree of biological species on Earth.

This represents a major paradigm shift as it introduces a retrospective element: one can only understand evolution by looking at it backwards in time. Deterministic and causal explanations apply only at a crude, coarse-grained level, while the precise way that structures and laws play out is governed by accumulated accidents. Essentially the question “how did everything start?” is superseded by the question “how did our universe become as it is today?” This may be seen as adopting a top-down view (into the past) instead of a bottom-up view (from the past).

Hawking criticised traditional cosmology for hiding certain assumptions, in particular the separation of the fundamental laws from initial boundary conditions and from the role of the observer. Instead, one should view the universe, at its most fundamental level, as a quantum superposition of many possible spacetimes, of which the observer is an intrinsic part.

From this Everettian viewpoint, wavefunctions behave like separate branches of reality. A measurement is like a fork in the road, where history divides into different outcomes. This line of thought has significant consequences. The author presents an illuminating analogy with the so-called delayed double-slit experiment, which was first conceived by John Archibald Wheeler. Here the measurement that determines whether an electron behaves as particle or wave is delayed until after the electron has already passed the slit. This demonstrates that the process of observation inflicts a retroactive component which, in a sense, creates the past history of the electron.

The fifth dimension 

Further ingredients are needed to transform this collection of ideas to a concrete proposal, argues Hertog. In short, these are quantum entanglement and holography. Holography has been recognised as a key property of quantum gravity, following Maldacena’s work on quantum black holes. It posits that all the information about the interior of a black hole is encoded at its horizon, which acts like a holographic screen. Inside, a fictitious fifth dimension emerges that plays the role of an energy scale.

A holographic universe would be the polar opposite of a Platonic universe with eternal laws

In Hawking and Hertog’s holographic quantum universe, one considers a Euclidean universe where the role of the holographic screen is played by the surface of our observations. The main idea is that the emergent dimension is time itself! In essence, the observed universe, with all its complexity, is like a holographic screen whose quantum bits encode its past history. Moving from the screen to the interior is equivalent to going back in time, from a highly entangled complex universe to a gradually less structured universe with fading physical laws and less entangled qubits. Eventually no entangled qubits remain. This is the origin of time as well as of the physical laws. Such a holographic universe would be the polar opposite of a Platonic universe with eternal laws.

Could these ideas be tested? Hertog argues that an observable imprint in the spectrum of primordial gravitational waves could be discovered in the future. For now, On the Origin of Time is delightful food for thought.

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It is rare and inspiring to be able to read the memoirs of a person who has celebrated their 100th birthday and yet is still exceptionally inquisitive and reflective. Herwig Schopper, director-general of CERN from 1981 to 1988, is one such person. In Scientist and Diplomat in a Changing World, he takes stock of his personal life, the development of physics, the political challenges he has faced, and the human interactions that knit each of these subjects together.

Schopper told the story of his life to co-author James Gillies, a particle physicist and former head of communications at CERN. Their interviews shed a brilliant light on his life. Starting work as a physicist in the field of optics, he moved first to study beta decays and parity violation, and then to nuclear and particle physics, accelerator physics and detector development more generally. Initial chapters cover his early years in what is today the Czech Republic, the dark years of war, and his studies in Hamburg from 1945 to 1954.

But though he loved to work hands on, Schopper was soon asked to found and direct institutes. His impact on nuclear and particle physics in Germany becomes eminently clear when he describes his career at the universities of Erlangen, Mainz, Karlsruhe and Hamburg. The book therefore next turns to time spent as a university professor establishing and directing institutes from 1954 to 1973, including productive sabbaticals in Stockholm, Cambridge and Cornell, and his journey to DESY via CERN between 1973 and 1980. It then explores his time as director-general of CERN from 1981 to 1988, his transition from science to diplomacy, his travels east and his impact on LEP and the LHC. These chapters are captivating, as they describe not only the life story of a remarkably active and productive scientist, but also the historical, scientific and political context in which the work was done.

Many people are happy to take life a little easier when they retire. Not so Herwig Schopper. For him, science is centre stage, and given his vast knowledge in science and science policy, his advice and help are still in high demand. A chapter on science for peace illustrates the rocky path he and dedicated colleagues took to create a science project in the Middle East, SESAME, with the goal to bring scientists from hostile countries to work together on excellent scientific projects.

While the main part of this very readable text describes the life and work of Schopper in the words of his co-author Gillies, each chapter ends with a section in Schopper’s own words in which he shares some very personal memories with the reader, speaking about his family and friends, and his deep love for music. The book also ends with an epilogue and some reflections by the man himself. Building on 100 years of experience, these words provide much food for thought.

Many of Herwig Schopper’s colleagues and friends have encouraged him to write about his life, as he has seen and done so many things. The result of those requests, this biography is a captivating documentation of an exemplary life in particle physics. But more than the story of a fulfilled life, this biography is a textbook about how scientific progress depends on individuals, scientific excellence, inspiration, perseverance and the fortune needed to bring it all off, as the French say.

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To help overcome these barriers, in 2022 the US CMS collaboration designed a pilot programme called PURSUE – the Program for Undergraduate Research Summer Experience. Due to the COVID pandemic, the collaboration initially worked virtually with 16 students, before an in-person pilot was launched in 2023. The programme has changed the career paths of several students, and a third edition with 20 undergraduates is now underway.

The power of collaboration

Two thirds of the HEP workforce go on to develop careers outside the field. The skills developed in HEP can lead to careers in many sectors, from software and electronics to health and finance. With skills-based labour markets currently a hot topic in business, a more guided and organised approach towards skills has the potential to reinforce the workforce pipeline for both HEP and industry, and benefit the many young researchers who look for jobs outside of academia.

The LHC experiments are a perfect seedbed for this. Comprising some 1200 physicists, graduate students, engineers, technicians and computer scientists from 55 universities and institutes, the US CMS collaboration each year trains about 200 students, 100 postdocs and produces 45 PhDs. It is therefore in a strong position to provide pathways to involve many young researchers in every aspect of the experiment and to prepare hundreds of next-generation scientists for careers in physics and industry alike.

The PURSUE undergraduate internship offers opportunities in state-of-art detector design and upgrades, operations, novel techniques in data taking and analysis, scientific presentations and international partnerships. It doesn’t matter if you are a US citizen or not. The basic requirement is that you are a student inside the US. This year’s cohort comprises students from Africa, South and Central America, and Asia.

This one-of-its-kind programme relies on a large team of dedicated collaborators

At the start of each year, invitations are sent out to all US CMS institutes asking them to propose projects and mentors. This year almost 30 applications were received, which were then matched as closely as possible to the individual interests of the students. Being a diverse and sprawling collaboration – rather than a single institution – is an attractive part of the programme.

At the beginning of the internship, all students meet at the LHC Physics Center at Fermilab for two weeks of software training, during which they gain skills in Unix, Python, machine learning and other areas that will equip them in any research area and throughout industry. This part of PURSUE was developed within the framework of the IRIS-HEP project, which is funded by the US National Science Foundation to address the computing challenges of the High-Luminosity LHC, and the CERN-based HEP Software Foundation. These skills are also key requirements for industry, with 42% of companies identifying AI and big data as a strategic priority for the next five years, according to the World Economic Forum’s Future of Jobs Report 2023.

During the remaining eight weeks of their internship, students travel to the US institution where their mentor is located. The students stay connected throughout this period via meetings and Zoom talks on physics and careers topics, and at the end of the programme they come together to produce a final presentation and poster. Some continue their research during the following semester, enabling a deeper dive into the field.

Success story

This one-of-its-kind programme relies on a large team of dedicated collaborators who take precious time out of their routines to battle the lack of diversity in HEP. And PURSUE’s interns are already succeeding. For example, from the 2022 cohort, Sneha Dixit has been admitted to graduate school at the University of Nebraska–Lincoln to pursue doctoral research on the CMS experiment, and Gabriel Soto has taken up a PhD in accelerator physics at the University of California Davis.

PURSUE also provides a way to engage new institutes with HEP. The initial funding for the programme was provided by a US Department of Energy grant awarded to Tougaloo College in Mississippi along with Brown University, the University of Puerto Rico and the University of Wisconsin. Tougaloo College had no previous connection to particle physics, but it is now hoped that it will become a member of the US CMS collaboration.

The driving force behind PURSUE was Meenakshi Narain of Brown University, an inspirational leader and champion of diversity in CMS and beyond, who passed away in January last year. We hope that the programme inspires similar initiatives in other experiments, fields and regions.

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Just married, and fresh from his PhD from University College London, Phil was recruited by CERN in November 1968 to work in the magnet group of the Intersecting Storage Rings (ISR) division, where his first task was to oversee the manufacture of the skew quadrupoles. The group, later renamed the beam optics and magnets group, was strongly involved in the commissioning and development of the collider. Phil set up and tested a low-beta scheme, built from recuperated iron-core magnets, to validate this technology for the ISR, paving the way for the first superconducting low-beta insertion in a working accelerator. Later, he led the design and construction of the beamline from the PS that enabled pp collisions at the ISR, a development with which he became deeply involved. His name is also associated with coupling compensation, and generally with the smooth operation of the collider until it closed in 1983.

A skilled communicator, Phil moved on to assist Kjell Johnsen with setting up the CERN Accelerator School (CAS). He served as director of the school from 1985 to 1991, delivering many lectures himself, and laying the foundations for it to become the valued institution that it is today. He then participated in a study of a B-meson factory for CERN before turning his attention to medical accelerators. Under his leadership this culminated in the Proton–Ion Medical Machine Study (PIMMS) of a synchrotron and its beamlines, which became the basis of the now operating medical centres for cancer treatment in Italy (CNAO) and Austria (MedAustron).

In addition to his managerial competence, Phil brought a contagious enthusiasm to the table

In the early 2000s, Phil joined the LHC effort, serving as chair of the specification committee and taking responsibility for the contract office. Having to navigate deadlines, he shuttled between physicists, engineers, procurement officers and CERN’s legal team. In addition to his managerial competence, Phil brought a contagious enthusiasm to the table, and would apply diplomatic skill in the conclusion of protocols with funding agencies and institutes. On his official retirement from CERN in 2007, Phil moved to Austria to be available for the medical facility under construction there. As this activity wound down, he increased his collaboration with the Vienna-based company Cividec, developing diamond radiation detectors, as well as continuing to improve the WINAGILE program that he had developed for accelerator design, and lecturing – notably for CAS and JUAS, the Joint Universities Accelerator School.

Phil enjoyed scientific work, developing new ideas and writing. The author of numerous papers, his 2012 report on the advancement of colliders due to work done at the ISR is exemplary. A prodigious worker, he was nevertheless modest and always anxious to acknowledge the contribution of collab­orators. Besides being a talented physicist and engineer, Phil was also good at drawing, his cartoons being especially appreciated. An inveterate “bricoleur”, when not busy advancing accelerator technology he was active with his hands at home. Phil will be sorely missed.

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Born in 1934 in the Ardèche in the South of France, Yves completed his studies at the Institut Polytechnique de Grenoble. He joined CERN in 1963 as engineer-in-charge of the Proton Synchrotron (PS) and quickly took a strong interest in analysing and improving the slow-ejection procedure. He became leader of the machine study team before moving to the Super Proton Synchrotron (SPS) project in the early 1970s, where his experience with beam extraction was very welcome.

Once the SPS extraction was operational at the end of the 1970s, Yves moved on to the Large Electron Positron (LEP) collider and, in particular, its injection system, which at the beginning was imagined as a new system without a link to the existing accelerators. His decisive idea to use the deadtime between the proton cycles of the SPS – dictated by limited cooling power – to insert the low-dissipation e⁺e^– acceleration cycles from 3.5 to 20 GeV was the key element for accepting the existing accelerator chain PS and SPS with all its infrastructure as the LEP injector. This cut short all discussions on other possible LEP sites in Europe.

After this memorable success with LEP, Yves moved back to his first love, the PS, and took responsibility for the PS ring proper to define and oversee an upgrade programme enabling the elderly machine to accelerate electrons and positrons from 0.6 to 3.5 GeV. The complete vacuum system had to be modified to withstand the synchrotron radiation emitted from the lepton beams, and the campaign reached its climax during a very long shutdown in 1987, during which a stainless-steel vacuum chamber was installed around the ring. Since the PS magnets had combined-focussing, i.e. a quadrupole magnetic field on top of the dipole field, the synchrotron radiation would not allow for stable operation. To counter this, two Robinson-type wiggler magnets had to be inserted. Yves and his team designed this unique magnet, tested the prototype in the PS and at the DCI ring at LAL in Orsay and, finally, introduced it successfully in the PS.

In the early 1990s, Yves went on to join the teams designing a beauty factory to be housed in the tunnel of the former Intersecting Storage Rings, and took the lead in the design of a tau–charm factory to be built on a green-field site in Spain. However, since these projects did not then materialise, he continued his work at the CLIC test facility to which the linear accelerator of LEP had to be converted. In 1984, in parallel with his other widespread activities, Yves took an active interest in the LHC design study, leading to the project’s official approval in 1994. He moved into project management in the mid-1990s and was entrusted with chairing the influential LHC parameter committee until his retirement in 1999.

Yves will be remembered for his thorough and well-thought approach to his work, always seeking to understand ab initio, and for his meticulous insistence on checking hardware through prototyping and extended testing. Unassuming but sharp and exacting, he was a well-respected colleague, an appreciated lecturer and a leader with wide-ranging interests.

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Stefano studied physics at the University of Florence and obtained his PhD in 1987 under the supervision of Marcello Ciafaloni, who passed away in September 2023. He was a postdoctoral fellow at the University of Cambridge from 1989 to 1991, and a member of CERN’s theory division from 1991 to 1993. After 1993 he developed his scientific career at INFN Florence, with a period as a CERN staff member between 1997 and 2002.

Discussing physics with Stefano was a fantastic experience. His depth and vision were simply unique. He was one of the great pioneers in the development of QCD as a precision science, thanks to his extraordinary ability to embrace the entire field without interruption, from the physics of “soft” gluons and their resummation to the perturbative regime. His research achievements are internationally recognised as being fundamental to the success of the high-energy collider physics programme, in particular for precision studies of the Higgs boson and the top quark.

His work is recognised as fundamental to the success of the high-energy collider physics programme

Among his most important contributions are the formulation of jet clustering algorithms at lepton and hadron colliders (a key component of most experimental analyses), a general expression for the determination of the infrared singularities of scattering amplitudes (the so-called Catani formula), the design of general algorithms for the perturbative calculation of cross sections and differential observables, which have become a standard in the community (the well-known Catani–Seymour dipole subtraction and the q_T subtraction schemes), and the innovative Catani–Krauss–Kuhn–Webber algorithm for Monte Carlo simulations of many-jet processes.

Stefano’s work was especially motivated by the application of QCD to collider data. He was convinced that our understanding of QCD singularities could be formulated in a way that any user could make a next-to-leading-order calculation of any suitable observable, not just dedicated calculations by experts. He also studied factorisation properties and coherence effects in the high-energy limit (the Catani–Ciafaloni–Fiorani–Marchesini equation) and proposed a generalisation of collinear factorisation that accounts for potential factorisation breaking effects at very high perturbative orders. The countless messages received from collaborators and colleagues all over the world, affected by the premature loss of a dear friend and extraordinary colleague, highlight Stefano’s great qualities of generosity, human warmth and scientific rigour that will be sorely missed by all.

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Jacques entered Ecole Normale Supérieure in 1954 and later went to Stanford, where he worked under Burton Richter on the pioneering Colliding Beam machine to collide electrons in flight using two storage rings. After his military service, Jacques joined the Laboratoire de l’Accélérateur Linéaire in Orsay, to undertake a doctorate on the AdA (Anello di Accumulazione) ring. Built in Frascati from an idea of Bruno Touschek to collide in-flight electrons and positrons stored in the same vacuum chamber, AdA had been brought to Orsay by Pierre Marin to take advantage of the high intensity of the linac beams. Jacques mastered all aspects of the ground-breaking experiment and succeeded in detecting the very first time-in-flight collisions in 1963.

In accelerator physics, following a discovery on the ACO ring at Orsay, Jacques published, in 1967, a basic paper on the longitudinal equilibrium of particles in a storage ring that contained the now widely used “Haïssinski equation”. He also collaborated with Stanford on the commissioning of SPEAR and later SLC, the very first and so-far only linear collider. In phenomenology, following Touschek, he led a programme on radiative corrections and later gave lectures on this subject in preparation for LEP at Ecole de Gif in 1989.

But the main scientific activity of Jacques Haïssinski was experimental particle physics. He took part in many experiments, directed theses in Orsay on ACO, and was spokesperson of the CELLO experiment at DESY. During the construction of LEP, Jacques served as chairperson of the LEP committee at CERN.

After LEP, Jacques turned his interests to astroparticle physics and cosmology, notably giving courses on the subject and collaborating on the EROS experiment and the Planck mission. During that time, he also took responsibilities in the management of Paris-Sud University (at Orsay), and later as a leader in IN2P3 and in the Saclay Laboratory DAPNIA (now IRFU). His leadership was greatly appreciated by the French high-energy physics community.

An outstanding teacher, Jacques also campaigned for the dissemination of knowledge to the public. He was a great humanist who was deeply concerned with social injustice and criminal wars. He presented his views publicly and believed that other physicists should do so. Generous with his precious time, he was always available to pass on his knowledge and vast scientific culture. He marked and inspired several generations of particle and accelerator physicists.

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Mats Lindroos, who made major contributions to accelerator technology, passed away on 2 May 2024 aged just 62.

Mats received his PhD in subatomic physics from Chalmers University of Technology in Gothenburg, Sweden in 1993 under the supervision of Björn Jonson. As a PhD student he studied decay properties and hyperfine interactions from oriented nuclei, making use of the low-temperature nuclear orientation facilities at ISOLDE, Daresbury and Studsvik. He joined CERN as a research fellow in 1993 and became a staff member in 1995.

While at CERN, Mats filled a number of diverse roles including being responsible for PS Booster operation and the technical coordination of the ISOLDE facility. He was one of the driving forces behind the HIE-ISOLDE project that commenced construction in 2009 and is now one of the major accelerated radioactive beam facilities worldwide. While at CERN he also played leading roles in several European Union-supported design studies for future conceptual accelerator facilities: the nuclear-physics radioactive beam facility EURISOL and the beta-beam neutrino factory. 

In 2009, when Sweden and Denmark were selected to be the host countries for the European Spallation Source (ESS), Mats returned to his roots in Sweden on secondment from CERN, formally joining the ESS in 2015. As one of the earliest members of the ESS organisation, he was responsible for establishing the nascent accelerator organisation as well as the accelerator collaboration, set up as a CERN-like collaboration, between major European accelerator laboratories across 10 countries to undertake the technical design of this important part of the facility. Mats led the technical design for the 5 MW proton linac of the ESS, and from 2013 as head of the 100-strong accelerator division he led the linac project that is now in the late stages of construction and installation. Even after stepping down from his leadership roles because of illness, he enthusiastically accepted a new one to advise the ESS management. He was fully involved in the process, and undoubtedly would have been instrumental in guiding the future evolution of the facility.

He set up a CERN-like collaboration between major European accelerator laboratories across 10 countries

As a globally recognised expert on accelerator technology, Mats served on many committees in an advisory role, such as the IJC Lab strategic advisory board (France), IN2P3 scientific committee (France), J-PARC technical advisory committee (Japan), PIP-II Fermilab technical advisory committee (US) and CERN’s scientific policy committee. As an adjunct professor at Lund University he enjoyed teaching and supervising students in addition to his numerous research, management and committee roles. Despite all these work activities, Mats found time to oversee, together with his partner Anette, the construction of a house on the south Swedish coast, where they enjoyed walking, gardening and being active in the local community.

Mats has touched all our lives with his energy and passion for research, his creativity for new ideas, his worldly knowledge, his sense of humour, and most importantly, his humanity and kindness. He will be greatly missed by all of us who had the privilege to count him as a friend and colleague.

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Six chapters cover Weinberg’s most consequential contributions to effective field theory, the Standard Model, symmetries, gravity, cosmology and short-form popular science writing. I can’t identify any notable omissions and I doubt many others would, though some may raise an eyebrow at the exclusion of his paper deriving the Lee–Weinberg bound. Duff brings each chapter to life with first-hand anecdotes and details that will delight those of us most greatly separated from historical events. I am relatively young, and only had one meaningful interaction with Steven Weinberg.  Though my contemporaries and I inhabit a scientific world whose core concepts are interwoven with, if not formed by, Steven Weinberg’s scientific legacy, unlike Michael Duff we are poorly qualified to comment historically on the ecosystem in which this legacy grew, nor on aspects of personality. This makes his commentary particularly valuable to younger readers.

I can envisage three distinct audiences for this new collection. The first is the lay theorist – those who are widely enough read to recognise the depth of Weinberg’s impact in theoretical physics and would like to know more. Such readers will find Duff’s introductions to be insightful and entertaining – helpful preparation for the more technical aspects of the papers, though expertise is required to fully grapple with many of them. There are also a few hand-picked non-technical articles one would otherwise not encounter without some serious investigative effort, including some accessible articles on quantum field theory, effective field theory and life in the multiverse, in addition to the dedicated section on popular articles. These will delight any theory afficionado.

The second audience is practising theorists. If you’re going to invest in a printed collection of publications, then Weinberg is an obvious protagonist. Particle theorists consult his articles so often that they may as well have them close at hand. This collection contains those most often revisited and ought to be useful in this respect. Duff’s introductions also expose technical interconnections between the articles that might otherwise be missed.

The third audience I have in mind are beginning graduate students in particle theory, cosmology and beyond. It would not be a mistake to put this collection on recommended reading lists. In due course, most students should read many of these papers multiple times, so why not get on with it from the get-go? The section on effective field theories (EFTs) contains many valuable key ideas and perspectives. Plenty of those core concepts are still commonly encountered more by osmosis than with any rigour, and this can lead to confused notions around the general approach of EFT. Perhaps an incomplete introduction to EFT could be avoided for graduate students by cutting straight to the fundamentals contained here? The cosmology section also reveals many important modern concepts alongside lucid and fearless wrestling with big questions. The papers on gravity detail techniques that are frequently encountered in any first foray into modern amplitudology, as well as strategies to infer general lessons in quantum field theory from symmetries and self-consistency alone.

In my view, however, the most important section for beginning graduate students is that on the construction of the Standard Model (SM). It may be said that a collective amnesia has emerged regarding the scientific spirit that drove its development. The SM was built by model builders. I don’t say this facetiously. They made educated guesses about the structure of the “ultraviolet” (microscopic) world based on the “infrared” (long-distance) breadcrumbs embedded within low-energy experimental observations. Decades after this swashbuckling era came to an end, there is a growing tendency to view the SM as something rigid, providentially bestowed and permanent. The academic bravery and risk-taking that was required to take the necessary leaps forward then, and which may be required now, is no better demonstrated than in “A Model of Leptons”. All young theorists should read this multiple times. A Model of Leptons exemplifies that not only was Steven Weinberg an unstoppable force of logic, but also a plucky risk taker. It’s inspirational that its final paragraph, which laid out the structure of nature at the electroweak scale, ends with doubt and speculation: “And if this model is renormalisable, then what happens when we extend it to include the couplings of A and B to the hadrons?” By working their way through this collection, graduate students may be inspired to similar levels of ambition and jeopardy.

Amongst the greatest scientists of the last century

In the weeks that followed the passing of Stephen Weinberg, I sensed amongst a number of colleagues of all generations some moods that I could have anticipated; of the loss of not only a bona fide truth-seeker, but also of a leader, frequently the leader. I also perceived a feeling that transcended the scientific realm alone, of someone whose creative genius ought to be recognised amongst the greatest of scientists, musicians, artists and humanity of the last century. How can we productively reflect on that? I imagine we would all do well to learn not only of Weinberg’s important individual scientific insights, but also to attempt to absorb his overall methodology in identifying interesting questions, in breaking new trails in fundamental physics, and in pursuing logic and clarity wherever they may take you. This collection is not a bad place to start.

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“He is a restless person,” noted Albrecht Wagner (DESY), who presented a whistlestop tour of Schopper’s 35 years working in Germany, following his childhood in Bohemia. Whether in Hamburg, Erlangen, Mainz or Karlsruhe, he never missed out on an opportunity to see new places – though always maintaining the Austrian diet to which his children attribute his longevity. On one occasion, Schopper took a sabbatical to work with Lise Meitner in Stockholm’s Royal Institute of Technology. At the time, the great physicist was performing the first nuclear-physics studies in the keV range, said Wagner, and directed Schopper to measure the absorption rate of beta-decay electrons in various materials using radioactive sources and a Geiger–Müller counter. Schopper is one of the last surviving physicists to have worked with her, observed Wagner.

Schopper’s scientific contributions have included playing a major part in the world’s first polarised proton source, Europe’s first R&D programme for superconducting accelerators and the development of hadronic calorimeters as precision instruments, explained Christian Fabjan (TU Vienna/HEPHY). Schopper dubbed the latter the sampling total absorption calorimeter, or STAC, playing on the detector’s stacked design, but the name didn’t stick. In recognition of his contributions, hadronic calorimeters might now be renamed Schopper total absorption calorimeters, joked Fabjan.

As CERN DG from 1981 to 1988, Schopper oversaw the lion’s share of the construction of the LEP, before it began operations in July 1989. To accomplish this, he didn’t shy away from risks, budget cuts or unpopular opinions when the situation called for it, said Chris Llewellyn Smith, who would himself serve as DG from 1994 to 1998. Llewelyn Smith credited Schopper with making decisions that would benefit not only LEP, but also the LHC. “Watching Herwig deal with these reviews was a wonderful apprenticeship, during which I learned a lot about the management of CERN,” he recalled.

After passing CERN’s leadership to Carlo Rubbia, Schopper became a fulltime science diplomat, notably including 20 years in senior roles at UNESCO between 1997 and 2017, and significant contributions to SESAME, the Synchrotron-light for Experimental Science and Applications in the Middle East (see CERN Courier January/Feb­ruary 2023, p28). Khaled Toukan of Jordan’s Atomic Energy Commission, CERN Council president Eliezer Rabinovici and Maciej Nałecz (Polish Academy of Science, formerly of UNESCO) all spoke of Schopper’s skill in helping to develop SESAME as a blueprint for science for peace and development. “Herwig likes building rings,” Toukan fondly recounted.

As with any good birthday party, Herwig received gifts: a first copy of his biography, a NASA hoodie emblazoned with “Failure is not an option” from Sam Ting (MIT), who is closely associated with Schopper since their time together at DESY, and the Heisenberg medal. “You’ve even been in contact with the man himself,” noted Heisenberg Society president Johannes Blümer, referring to several occasions Schopper met Heisenberg at conferences and even once discussed politics with him.

Schopper continues to counsel DGs to this day – and not only on physics. Confessing to occasionally being intimidated by his lifetime of achievements, CERN DG Fabiola Gianotti intimated that they often discuss music. “Herwig likes all composers, but not baroque ones. For him, they are too rational and intellectual.” For this, he will always have physics.

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Peter Higgs was born in Newcastle upon Tyne in the UK on 29 May 1929. His family moved around when he was young and he suffered from childhood asthma, so he was often taught at home. However, from 1941 to 1946 he attended Cotham Grammar School in Bristol, one of whose alumni was Paul Dirac. He went on to study physics at King’s College London, where he got his bachelor’s degree in 1950 and his PhD for research in molecular physics in 1954. After periods at the University of Edinburgh, Imperial College and University College London, in 1960 he settled at the University of Edinburgh where he remained for the rest of his career.

Seeds of success

Following his PhD, Higgs’s research interests shifted to field theory, with a first paper on vacuum expectation values of fields in 1956, followed by a couple of papers on general relativity. Then, in 1964, came his two famous papers introducing spontaneous gauge symmetry breaking into relativistic quantum field theory and showing how a vector boson could acquire a mass in a consistent manner – as long as it was accompanied by a massive scalar boson.

Related ideas had been discussed previously by Phillip Anderson and Yoichiro Nambu in the context of non-relativistic condensed-matter physics, namely in models of superconductivity, where a condensate of electron pairs enables a photon to acquire an effective mass. Anderson conjectured that a similar mechanism should be possible in a relativistic theory, but he did not develop the idea. On the other hand, Nambu used spontaneous symmetry breaking to describe the properties of the pion, but also did not discuss the extension to a relativistic vector boson.

In early 1964 Walter Gilbert (later a winner of the Nobel Prize in Chemistry) wrote a paper arguing that Anderson and Nambu’s ideas for generating mass for a vector boson could not work in a relativistic theory. This was Higgs’s cue: a few weeks later he wrote a first paper pointing out a potential loophole in Gilbert’s argument (though not a specific model). He sent his paper to the journal Physics Letters, which quickly accepted it for publication. A few days later, he wrote a second paper, which contained an explicit model for mass generation, but was taken aback when the same journal rejected this paper as not being of practical interest. Undeterred, Higgs tweaked his paper to make his message more explicit, and submitted it to Physical Review Letters, where it was accepted.

Unknown to Higgs, François Englert and Robert Brout had already sent a paper describing a similar model to the same journal, where it was published ahead of Higgs’s paper. Both papers postulated a scalar field with a non-zero vacuum expectation value that gave mass to a vector boson. However, there was a key difference: Higgs pointed out explicitly that his model predicted the existence of a massive scalar boson, whereas this was not mentioned in the Englert–Brout paper. For this reason, the particle he predicted became known as the Higgs boson. Shortly after the publication of the Higgs and Englert–Brout papers, Gerry Guralnik, Carl Hagen and Tom Kibble published an article referring to their papers and filling in some aspects of the theory, but also not mentioning the existence of the massive scalar boson.

In 1965 Higgs went for a sabbatical to the University of North Carolina, where he continued working on his theory. Remarkably prescient, he wrote a third paper discussing how his boson could decay into a pair of massive gauge bosons as well as calculating associated scattering processes. However, he encountered scepticism about the validity of his theory, and neither his nor the other pioneering mass-generation papers garnered significant attention for several years.

This started to change in 1967 and 1968 when Steven Weinberg and Abdus Salam incorporated the mass-generation mechanism into their formulation of the electroweak sector of the Standard Model. But interest only really took off a few years later, after Gerard ’t Hooft and Martinus Veltman showed that spontaneously broken gauge theories are renormalisable and hence could be used to make accurate and reliable predictions for comparison with experiment, and when neutral weak interactions were discovered in the Gargamelle bubble chamber at CERN in 1973.

The search begins

During the 1970s interest in the experimental community moved towards searches for the massive intermediate vector bosons, the W and Z. However, it seemed to Mary Gaillard, Dimitri Nanopoulos and myself that the key long-term target should be the Higgs boson, the capstone of the structure of the Standard Model, and in 1975 we wrote a paper describing its phenomenology. At the time the existence of the Higgs boson was still regarded with some scepticism, and we ended our paper by writing that “We do not want to encourage big experimental searches for the Higgs boson, but we do feel that people performing experiments vulnerable to the Higgs boson should know how it may turn up.” I met Peter Higgs for the first time around 1980, and he was clearly flattered by our interest in his boson, but unprepared for the subsequent interest in the big experimental searches that followed.

Higgs pointed out explicitly that his model predicted the existence of a massive scalar boson

Searching for the Higgs boson moved to the top of the agenda following the discovery of the W and Z at CERN in 1983, when the Superconducting Super Collider project was launched in the US, followed by the first LHC workshop in 1984. Being a profoundly modest man, Higgs followed these developments from a distance as a somewhat bemused spectator. In the 1990s, precision experiments at LEP and elsewhere confirmed predictions of the Standard Model with high accuracy – if and only if the Higgs boson (or something very like it) was included in the theoretical calculations. Higgs became quietly confident in the reality of his boson. By the time the LHC started accumulating collisions at an energy of 7 and 8 TeV, anticipation of its possible discovery was growing.

Following early hints at the end of 2011, the word went around that on 4 July 2012 the ATLAS and CMS experiments would give a joint seminar presenting their latest results. I was tasked with locating Higgs and persuading him that he might find the results interesting. Somewhat reluctantly, he decided to come to CERN for the seminar, and he had no cause to regret it. He wiped tears from his eyes when the discovery of a new particle resembling his boson was announced, and confessed that he had never expected to see it in his lifetime.

Famously, in October 2013 as the Nobel Prize was being announced, Higgs went missing, in order to avoid being thronged by the media. Some months previously, in a pub in Edinburgh, he had told me that the existence of the Higgs boson was not a “big deal”, but I assured him that it was. Without his theory, electrons would fly away from nuclei at the speed of light and atoms would not exist, and radioactivity would be a force as strong as electricity and magnetism. His prediction of the existence of the particle that bears his name was a deep insight, and its discovery was the crowning moment that confirmed his understanding of the way the universe works.

Peter Higgs is survived by his two sons, a daughter-in-law and two grandchildren.

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In 1974 Igor Savin led a small group of physicists from Dubna to visit CERN to identify an experiment where JINR’s participation would be significant. Thanks to his enthusiasm and organisational talent, this led to the first large-scale joint CERN–JINR project, NA4 at the SPS, which was approved in 1975 and finished in 1995. He led the JINR team participating in the study of deep inelastic scattering of muons from nucleons and nuclei. This research established γ/Z interference in the electroweak interactions of muons on nuclei, indicating the existence of an intermediate Z-boson discovered at CERN a year and a half later, and enabled the structure functions of protons and deuterons to be measured at percent levels. The latter were shown to be in agreement with the new theory of strong interactions, QCD, and proved that the structure functions of free and bound nucleons in the nucleus differ. This first equal cooperation between JINR and CERN contributed to the development at Dubna of the most advanced technologies and promoted strong collaboration with the global scientific community.

Igor Savin founded a new scientific direction at JINR: the experimental and theoretical study of the spin structure of nucleons and nuclei, which has gone from strength to strength. Igor headed the JINR group in the SMC experiment at CERN, in which the spin-dependent structure functions of protons and deuterons were measured and a small contribution of the valence quarks to the nucleon spin was found. He also led the JINR team in the COMPASS experiment at CERN and actively participated in the HERMES experiment at DESY to further study the nucleon spin structure in electron scattering reactions on longitudinally and transversely polarised nucleons.

As director of VBLHEP JINR, Igor Savin paid great attention to the development of international scientific cooperation, which is the backbone of the laboratory. The main task was to perform research at external accelerators at IHEP, CERN, DESY, Brookhaven and other world centres. His work has been recognised with numerous awards, including the gold medal of the Czech Academy of Sciences and the medals of the Hungarian People’s Republic and the German Democratic Republic. He was a scientist with a worldwide reputation, who helped create the glorious history of JINR. On the occasion of his 90th birthday, Carlo Rubbia said: “Igor, your anniversary celebration represents for all of us a unique result to which we have been involved over many decades and of which we are extremely proud”.

Igor Savin leaves a deep mark on science and a bright memory to everyone who had the honour and privilege to call him their friend, colleague or mentor. A wonderful man and a true scientist will be missed by all who knew and loved him.

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After studying physics at the Technical University of Munich and completing his diploma thesis under the supervision of Paul Kienle, Fritz Nolden began working at GSI Darmstadt in July 1985. His work focused on aspects of the planned Experimental Storage Ring (ESR) in Bernhard Franzke’s group. Initially he dealt with general questions regarding the interpretation and design of the storage ring and related beam-dynamics aspects. Here he benefited from his ability to work on theoretical problems, which played a major role in his further career and which, as he always liked to emphasise, was the greatest motivation and basis for his work.

After working intensively in the construction and commissioning of the ESR, Nolden increasingly found time to deal with the theory and structure of stochastic cooling. This led to the completion of his doctoral thesis at the Technical University of Munich in 1995 on theoretical aspects of a stochastic cooling system at the ESR. He was responsible for the commissioning of this system at the ESR in the same year, and worked on a variety of problems that arose during the operation of the ESR facility, both theoretically and experimentally. Colleagues from the research departments also appreciated his support, in both words and actions, when planning and carrying out experiments at the ESR.

In addition to his ongoing willingness to ensure the operation of the ESR in a jointly responsible position, he also increasingly took on tasks in planning the storage rings for FAIR and in particular their stochastic-cooling systems. Many criteria and specifications of these systems go back to his theoretical work and planning activities.

Until his retirement in 2017, Nolden continued to support the operation of the ESR with all his expertise and commitment. After his retirement, he still visited GSI regularly to discuss current issues with colleagues and share his wealth of experience with them. He was a sought-after conversation partner because he not only brought his expertise to the discussions, but also liked to season his comments with subtle humour.

Fritz’s professional contributions were also valued by many international colleagues, for whom he was an open and competent partner in scientific exchange. Worth mentioning here are his many years of exchange with colleagues at CERN and his consulting work at the IMP Lanzhou.

We mourn the loss of a colleague with excellent specialist knowledge, great interest and commitment in his tasks for GSI and FAIR, who always showed a friendly manner and a great openness to all the problems that were brought to his attention.

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Pathak completed his master’s degree in physics from the University of Calcutta in 1956, with a specialisation in nuclear physics and cosmic radiation. The following year, he started as a lecturer in physics at Cotton College, Guwahati. With his zeal to scale new heights, he left for England and started research at Durham University under the guidance of Astronomer Royal Arnold W Wolfendale. He received his PhD in 1967 for his work on high-energy cosmic rays.

It is praiseworthy that instead of continuing research abroad in highly sophisticated labs, Kishori returned to his native land with a strong determination to motivate the talented young people of the region towards higher studies in the upcoming field of cosmic-ray physics. Soon after returning to Assam in 1969, he successfully established a research group in the physics department of Gauhati University, which was dedicated to studies of the electromagnetic radiation at radio and optical Cherenkov frequencies from ultra-high-energy (> 10¹⁶ eV) cosmic-ray showers. His research activities saw him visit and interact with cosmic-ray physicists at CERN and Munich University, and in 1995 he was recognised by his election as a fellow of the UK Institute of Physics.

As well as cosmic-ray physics, Kishori Pathak collaborated with geologists at Gauhati University. Using the technique of fission track dating, he successfully dated rocks and minerals of the Meghalaya Plateau in the northeastern region of India for the first-time, providing data of great importance in determining the geological formation of the plateau as well as the natural resources for the economic development of the region. He also extensively studied the probable effect of uranium content in water from various sources of the whole of the northeastern region of India, which had a high incidence of cancer, and in the 1980s made extensive futurological studies on the problems of higher education in the region. This experience helped Pathak while setting up the Central University of Tezpur, which is now one of the most sought-after institutions of higher education in India, with a national and international reputation. In recognition of his contributions towards society, he received the Outstanding Service Gold Medal from the Governor of Assam in 1991 and was selected for the Lifetime Achievement Award in the 2023 State Science Awards.

Kishori Pathak will be remembered as a brilliant cosmic-ray physicist and a great academician who worked wholeheartedly throughout his entire life to uplift the people around him.

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A significant role in Shulga’s formation as a scientist was played by his PhD advisor and prominent KIPT theorist Oleksandr Akhiezer. Together they developed the quasi classical theory of coherent radiation of channelled and over-barrier electrons and positrons in crystals. This theory provided an understan­ding of the basic emission mechanisms in oriented crystals, which is crucial for creating an intense gamma-ray source as well as a crystal-based positron source for future electron–positron colliders.

Mykola Shulga always worked to ensure that his theoretical predictions were tested experimentally. Many of them were confirmed recently at CERN. In 2005–2010 the NA63 collaboration confirmed the Ternovsky–Shulga–Fomin effect – a suppression of bremsstrahlung radiation from ultrarelativistic electrons in thin layers of matter. In 2009–2017 the UA9 collaboration confirmed his prediction of a stochastic Grinenko–Shulga mechanism of high-energy particle-beam deflection by a bent crystal. This mechanism allows the deflection of both positively and negatively charged particles, and is planned to be implemented at the PETRA IV synchrotron at DESY and future electron–positron colliders.

Shulga was a laureate of the State Prize of Ukraine in the field of science and technology (2002), won prizes of the National Academy of Sciences of Ukraine (NASU) named after O S Davydov (2000) and O I Akhiezer (2018), and received many other awards. In 2009 he was elected an academician of NASU and in 2015 became head of its department of nuclear physics and power engineering. From 2004 to 2013 he was vice-president of the Ukrainian Physical Society.

Shulga paid great attention to working with young physicists, whom he taught for many years at V N Karazin Kharkiv National University. He trained eight PhD students and eight doctors of science, and among his students are eight laureates of the State Prize of Ukraine in the field of science and technology.

Thanks to his high human qualities, exceptional diligence and amazing capacity for work, Mykola Shulga gained great authority and respect in the scientific community. He led National Science Center KIPT (NSC KIPT) through two years of the full-scale invasion of Ukraine by the Russian Federation, working to eliminate the consequences of more than 100 missile strikes on the NSC KIPT territory, which left not a single building undamaged. Undeterred by the war, until his last days he continued to promote the creation of a new international centre for nuclear physics and medicine on the NSC KIPT site (CERN Courier January/February 2024 p30).

His bright memory will forever remain in the hearts of his colleagues, friends, relatives and loved ones.

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Bruce completed his PhD at the University of Manchester, and his thesis research included work at the ISOLDE facility at CERN, which he later joined as a fellow in 2006 before taking up a staff position in 2010. In his different roles, Bruce contributed greatly to the development of the resonance ionisation laser ion source (RILIS) techniques dedicated to the production of radioisotopes for fundamental research and medicine at ISOLDE. The ISOLDE RILIS system has become a reference for all radioactive ion-beam facilities worldwide. Furthermore, Bruce worked closely with his team to contribute to the advancement of future accelerators and colliders at CERN, with a particular focus on CLIC, AWAKE and the Gamma Factory.

His work extended beyond CERN, influencing the global landscape of nuclear-structure and laser-physics research. He was a leading expert in the development and applications of RILIS-based in-source resonance ionisation spectroscopy. The technique allowed studies of nuclear ground- and isomer-state properties of radioactive isotopes, including recent investigations in mercury and bismuth isotopes that gained wide attention outside nuclear physics. Bruce authored articles in many high-impact journals and was invited to present his work at numerous international conferences, workshops and schools, many of which he helped to organise.

Bruce also achieved international recognition through his role as the coordinator of the European Union-funded Marie Skłodowska-Curie training network Laser Ionisation and Spectroscopy of Actinides (LISA), which comprises a dozen laboratories in Europe, several other international partners and 15 doctoral students, who explore the structure of the actinide elements.

Bruce will be fondly remembered for his warm and welcoming spirit – always ready with a smile for everyone – and for his strong sense of justice. An unwavering champion of diversity in the workplace, Bruce fostered an inclusive environment where every voice was valued, and every individual felt empowered to contribute to shared goals with their unique perspectives. He provided invaluable opportunities for integration, learning and professional growth for his colleagues and was always available for advice on professional and private matters. Despite his wealth of knowledge and accomplishments, he remained humble in all situations, leaving a lasting impact on all who knew him.

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IceCube’s 5160 optical sensors positioned deep within the Antarctic ice detect around 100,000 neutrinos per year, some of which are the most energetic events ever recorded. To make sure that the detector is operational throughout the year, people are required to spend extended periods at the South Pole, where temperatures are on average around –60°C during the winter.

Marc Jacquart was one of two “winterovers” for IceCube during the season November 2022 to November 2023. Having completed his master’s degree, during which he analysed IceCube data, he saw an internal email about the position and applied: “It was a long-time dream-come-true. I had wanted to go to the South Pole since I heard about IceCube six years earlier.” First he had to pass medical tests, a routine requirement for winterovers because it is difficult to evacuate people during the winter. His next stop was the University of Wisconsin–Madison, the lead institution for the IceCube collaboration, where he and his colleague Hrvoje Dujmović received three months’ training on how to operate, troubleshoot, calibrate and repair IceCube’s hardware and software components using a small replica of the data centre. “Our job is to ensure the highest detector uptime, so we need to know how to fix a problem immediately if something breaks.”

The pair made their way to McMurdo Station on the shores of Antarctica closest to New Zealand in early November 2022. From there, a plane took them 1350 km to the Amundsen–Scott station, located 2835 m above sea level and only 150 m from the geographic South Pole. During the summer, up to 150 people stay at the station to make major repairs and upgrades to the research facilities, which also include the South Pole Telescope, BICEP and an atmospheric research observatory. By mid-February, most people leave. “We were only 43 winterovers left, and that’s when you can help each other and busy yourself with all kinds of things,” says Marc.

Part of station life is volunteering for teams, which in Marc’s case included the fire fighters, amongst others. To bide their time during a nearly six-month-long night, the inhabitants can go to the library, music room or grow vegetables in a repurposed biology experiment to freshen up the preserved foods. While winter in the Antarctic Circle is harsh outside, says Marc, it has one major highlight: the southern lights. “I remember one time, they were just dancing, moving and very bright. We stayed outside for a full hour packed in layers and layers of clothes!”

The only real downtime for the detector is when operators perform a full restart every 32 hours

As a winterover, Marc ensured that the IceCube detector worked 24/7 and recorded every incoming neutrino. “Usually, we have 99.9% uptime. If there is something wrong, we have a pager that pings us, even in the middle of the night.” To ensure that the rarest high-energy neutrinos are recorded, the only real downtime for the detector, he says, is when operators perform a full restart every 32 hours. For such events, which could point to high-energy phenomena in the universe, IceCube sends a real-time alert to other experiments. About 200 machines are located in the data centre and collect 1 TB of data per day, only 10% of which are sent north to a data centre in the US due to satellite-bandwidth limitations. The remaining data gets stored on hard drives, which must be swapped manually by the winterovers every two weeks. During the summer, when aircraft can reach the South Pole on a regular basis, boxes stashed with hard drives are taken back for thorough data analysis and archiving.

Since returning home to Switzerland, Marc is considering his next steps. “I have the opportunity to work on a radio observatory in the US next year. After a year operating the IceCube detector, I’m interested to work with hardware more. And I am definitely considering a PhD with IceCube afterwards, as there is a lot coming up.” Currently, the IceCube collaboration is working towards IceCube-Gen2, with the first step being to add seven strings with improved optical modules to the existing underground complex. In a second step, 120 further cables with refined light sensors will optimise the detector, and two radio detectors as well as an extended array will be placed on the surface. The upgrades will enlarge IceCube’s coverage from one to eight cubic kilometres, offering more than enough tasks for future winterovers during the decade . “Maybe in a few years I would be keen to return to the South Pole. It’s a very special place.”

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Born in Messina, Italy in 1926, Giuseppe studied physics at the University of Rome, graduating in 1947 under the supervision of Edoardo Amaldi. Amaldi had become interested in cosmic rays and asked young “Pippo” to help him build a large detector to study the scattering of mesons on an iron target to explore the nuclear force. Between 1952 and 1954, Giuseppe continued to work on cosmic rays at the Tête Grise laboratory, 3500 m above Cervinia, where Maria Cervasi, whom he had met during his studies at Rome, also worked.

In 1953 Amaldi, who had become secretary general of the provisional CERN, suggested that Giuseppe spend time at the University of Liverpool to learn from the new synchrocyclotron being built there. He went to CERN with Maria, by then his wife, in 1956 and began preparing experiments for the 600 MeV Synchrocyclotron (SC), which came into operation in August 1957.

In January 1958, during a conference in New York, Giuseppe attended a presentation by Feynman describing the universal “V–A” theory of weak interactions. He heard that the theory lacked a key experimental ingredient: the decay of a pion into an electron and neutrino, predicted to occur 10 000 times less frequently than to a muon and a neutrino, which had not been observed in two experiments performed by well-known physicists. Upon his return to CERN, Pippo decided with the other members of the SC group that this would be the target of the next experiment. A device was immediately designed and built, and 40 events in perfect agreement with the V–A prediction were presented by Pippo in September 1958. The news put the newly born CERN on the map of the world of particle physics and laid the groundwork for the future discoveries of neutral currents, the W and Z bosons, and the Higgs field.

In 1960, with the start-up of the PS, Giuseppe led his group to measure – using a system of precision scintillators – the antiproton–proton cross section. The following year, he became professor at the University of Trieste and established a group that carried out a series of important scattering measurements at the PS and the SPS, in particular using polarised targets, during the 1970s. Following the proposal and execution of an experiment at the ILL in Grenoble searching for possible neutron–antineutron oscillations, in 1990 he presented an article “Fixed target B-physics at the Large Hadron Collider” at the LHC workshop in Aachen, which proposed, among other things, the use of a very intense proton beam extracted from the accelerator with a crystal, similar to what had been envisaged for the Superconducting Super Collider. This, and discussions with Giovanni Carboni and Walter Scandale, were at the origin of the RD22 collaboration, which for the first time proved the possibility of high-efficiency proton extraction from an accelerator using a bent crystal – a technique that is now used in LHC beam collimation.

Outside physics, Giuseppe made numerous contributions to CERN. In the early 1960s he was a member of the founding committee of the International Center for Theoretical Physics. In 1975 he was appointed as co-chair of a joint scientific committee set up under a collaboration agreement between CERN and the former USSR concerning the use of atomic energy, a responsibility he held until 1986. He was also tasked with coordinating cooperation with JINR in Dubna.

Giuseppe officially retired in 1991 but, together with Maria, continued his work at CERN as an honorary member of the personnel until as recently as 2020, during which time he devoted himself to research in the history of physics. He produced reports of rare beauty and precision, notably three well-documented articles on the contributions of Bruno Pontecorvo, whose friend he became in Dubna in 1989. Giuseppe was also known to CERN visitors, featuring prominently in the film shown in the Synchrocyclotron exhibition. Maria Fidecaro, with whom his rich human and scientific journey was deeply entwined, passed away in September 2023.

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Alongside Robert Brout and François Englert, and building on the work of a generation of physicists, Higgs postulated the existence of the Brout–Englert–Higgs (BEH) field. Alone among known fundamental fields, the BEH field is “turned on” throughout the universe, rather than flickering in and out of existence and remaining localized. Its existence allowed matter to form in the early universe some 10^–11 s after the Big Bang, thanks to the interactions between elementary particles (such as electrons and quarks) and the ever-present BEH field. Higgs and Englert were awarded the Nobel Prize for Physics in 2013 in recognition of these achievements.

An immensely inspiring figure for physicists around the world

Fabiola Gianotti

“Besides his outstanding contributions to particle physics, Peter was a very special person, an immensely inspiring figure for physicists around the world, a man of rare modesty, a great teacher and someone who explained physics in a very simple yet profound way,” said CERN’s Director-General Fabiola Gianotti, expressing the emotion felt by the physics community upon his loss. “An important piece of CERN’s history and accomplishments is linked to him. I am very saddened, and I will miss him sorely.”

Peter Higgs’ scientific legacy will extend far beyond the scope of current discoveries. The Higgs boson – the observable “excitation” of the BEH field which he was the first to identify – is linked to some of most intriguing and crucial outstanding questions in fundamental physics. This still quite mysterious particle therefore represents a uniquely promising portal to physics beyond the SM. Since discovering it in 2012, the ATLAS and CMS collaborations have already made impressive progress in constraining its properties – a painstaking scientific study that will form a central plank of research at the LHC, high-luminosity LHC and future colliders for decades to come, promising insights into the many unanswered questions in fundamental science.

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Dieter studied physics at the University of Bonn, where he joined the group of Helmut Piel, which had just started working on superconducting accelerator resonators. He then followed Piel, who had accepted an appointment as professor at the newly founded University of Wuppertal, and completed his doctorate on measurements of superconducting accelerator resonators. Soon after, he analysed the serious problem of so-called one-point multipacting in superconducting resonators prevalent at the time. Together with Wuppertal colleagues, he proposed changing the shape of resonators to have a spherical profile, which solved the multipacting problem. Subsequently, Dieter completed research stays at Cornell and CERN, where in 1981 he contributed to the development of spherical superconducting resonators for LEP II to double the energy of LEP. He then took up a permanent position at DESY, where he remained for almost 27 years until June 2009.

During his first years at DESY, Dieter’s focus was on the development of superconducting accelerator structures for the HERA accelerator that was being planned. He was head of the “Superconducting acceleration sections” experimental programme, where he demonstrated organisational talent as well as scientific and technical skills. Within a few years he pushed superconducting resonators from theoretical considerations to preliminary technological studies, and the operation of experimental resonators in the PETRA accelerator.

In the mid-1980s, Dieter took over a group focusing on superconducting accelerator technology. The group was responsible for the design, manufacturing, testing, installation and operation of the superconducting resonators in HERA.

In addition, Dieter was one of the founders of the international TESLA collaboration. Under his leadership, a groundbreaking infrastructure for the treatment, assembly and testing of superconducting accelerator resonators was built at DESY. This development work made it possible to increase the originally targeted field gradients from 25 to 35 MV/m. He organised close collaborations with many laboratories in Germany, Europe, Asia and the US. Particularly noteworthy here are Peking University and Tsinghua University, both of which appointed Dieter as a visiting professor.

As a globally recognised expert and deputy chair of the TESLA technology collaboration, Dieter served on important committees for many years, such as the advisory board for SNS at Oak Ridge. At DESY, the FLASH and European XFEL user systems are based on his fundamental work. The SRF Workshop, which later became a recognised international conference, was always particularly close to his heart. The scientific reputation that DESY enjoys worldwide was significantly influenced by Dieter. He also collaborated on several articles for the Handbook of Accelerator Physics and Engineering.

Dieter’s contributions continue to shape our understanding and advancement of accelerator technology. We thank him very much and will always remember him fondly.

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Since its inception a decade ago, the Future Circular Collider (FCC) collaboration has evolved in scope and scale – especially since the completion of the conceptual design report in 2018, when directed efforts were made to broaden the project’s reach and attract new partners. Such endeavours are crucial considering the ambitious nature of the FCC project and the immense global collaboration required to bring it to fruition.

Today, the collaboration brings together more than 130 institutes from 31 countries. Contributions from members span a broad spectrum encompassing theoretical and experimental particle physics, applied science, engineering, computing and technology. Ongoing collaborations with research centres internationally are pushing the performance of key technologies such as superconducting radio-frequency cavities and klystrons, as well as magnets based on novel high-temperature superconductors (see “Advancing hardware“). Increased global collaboration is a prerequisite for success, and links with high-tech industry will be essential to further advance the implementation of the FCC.

The proposed four-interaction point layout for the FCC is not only designed to offer the broadest physics coverage, but makes it a future collider commensurate with the size and aspirations of the current high-energy physics community. The attractiveness of the FCC is also reflected in the composition of participants at annual conferences, which shows a good balance between early-career and more senior researchers, geographical diversity, and gender. The latter currently stands at a 70:30 male-to-female ratio, which has been increasing during the course of the feasibility study.

Global working group

The FCC feasibility study has established a global working group with a mandate to engage countries with mature communities, a long-standing participation in CERN’s programmes, and the potential to contribute substantially to the project’s long-term scientific objectives. In addition, an informal forum of national contacts allows exchanges between physicists from different countries and the development of collaborations inside FCC. Each interested country has one or two national contacts who have the opportunity to report regularly on the development of their FCC activities.

Drawing parallels with the LHC and HL-LHC successes, CERN’s unique experience with large-scale scientific collaborations has been invaluable in shaping the cohesive and productive environment of the FCC collaboration. It is imperative to recognise the dedication of existing members while addressing the need for new contributors to bolster the collaboration. As the FCC considers the next stage of its scientific journey, potential partners are invited to bring their unique skills and perspectives.

First discussions on the governance and financial considerations for the FCC project are taking place in the CERN Council. The models aim to provide a structure for both the construction and operation phases, and assume compatibility with the CERN Convention, while also taking into account the United Nations’ sustainable development goals. In parallel, the organisational structure of the FCC experiment collaborations is being discussed. Given the inherently cooperative and distributed nature of these collaborations, a relatively lightweight structure will be put forth, based on openness, equality at the level of participating institutes and a wide consultation within the collaboration for key decisions.

Since 2021, the FCC has implemented a robust organisational structure, acting under the authority of the CERN Council, that facilitates efficient communication and coordination among its members. Looking ahead, the path to the governance model required for the FCC project and operation phases is both exciting and challenging. Importantly, it requires the long-term engagement and support of participants from CERN’s member and associate member states, and from the non-member states, whose community at CERN has been growing with the LHC, particularly from institutes located in North America and the Asia-Pacific regions. As the project evolves further, it is crucial to refine and adapt the collaboration model to ensure the efficient allocation of resources and sustained momentum.

The FCC offers a multitude of R&D opportunities, and the collaborative spirit that defines it promises to shape the future of particle physics. As we go forward, the FCC collaboration beckons individuals and institutions to contribute to the next chapter in our exploration of the fundamental laws and building blocks of the universe.

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In the aftermath of World War II, nations came together and formed the United Nations (UN) with the purpose, as stated in the first article of the UN charter, “… to take effective collective measures for the prevention and removal of threats to the peace”. With more than 100 ongoing wars and military conflicts, we are further away than ever from this ideal. This marks a significant failure of diplomacy to prevent those wars.

 The invasion of Ukraine by the army of the Russian Federation at the end of February 2022 and the suffering inflicted on countless innocent civilians, including scientists, is against international law and must be condemned in the strongest terms. Despite pro-war statements from some Russian institutes, many Russian physicists oppose the war and immediately signed petitions against it.

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Born on 8 August 1934 in Moscow, Golutvin graduated from MIPT in 1957 and started his work at JINR in 1958. Several generations of detectors for large-scale physics facilities were developed under his supervision at the JINR Synchrophasotron, the IHEP accelerator in Serpukhov, and at the Proton Synchrotron and the LHC at CERN.

Golutvin became one of the pioneers of the CMS experiment, driving the cooperation of Russia and other JINR member states via the Russia and Dubna Member States (RDMS) CMS collaboration. Over the past 30 years, under his supervision, RDMS physicists have completed the development of unique detectors for CMS. Igor was also instrumental in initiating Grid computing for CMS in Russia. He was awarded the 2014 Cherenkov Prize of the Russian Academy of Sciences for his outstanding contribution to the development of CMS. In recent years, he played an important role in the preparation of upgrades for CMS, in particular concerning the calorimeters.

During his work at JINR, Golutvin established a scientific school and trained a team of active, qualified physicists and engineers. Within the framework of cooperation between CMS Russia and other JINR member states, he brought together like-minded people with the aim of preserving Russian scientific schools, built unique teams of engineers and physicists, and developed favourable conditions for attracting gifted young physicists, which he saw as extremely important for the implementation of long-term scientific projects.

Igor was a member of the equipment committee of the International Committee for Future Accelerators, an editorial board member of the journal Nuclear Instruments and Methods, a directorate member of the CMS collaboration at CERN, head of the collaboration of the institutes of Russia and JINR in CMS, and the organiser and head of numerous international and Russian scientific conferences and symposia.

He was also a professor/full member of the Russian Academy of Engineering Sciences, Russian Academy of Natural Sciences, International Academy of Sciences, Honoured Scientist of the Russian Federation and chief researcher for CMS at VBLHEP. For many years of fruitful work, Golutvin was awarded numerous state and scientific awards and prizes.

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As a research associate at Berkeley (1969–1970) and a fellow at CERN (1972–1974), Ciafaloni initially focused his research on high-energy soft hadronic physics and produced important results in the context of Reggeon field theory. Towards the end of the seventies, he shifted his attention to perturbative QCD, in particular to hard processes and small-x physics where sophisticated re-summation techniques are needed. Since then, and throughout his career, he produced many fundamental results in perturbative QCD, including his single-author contribution to the celebrated CCFM equation (where the first C stands for his name), an important ingredient for QCD-based event generators.

Since 1987, Ciafaloni added a second dimension to his research spectrum by devoting part of his activity to the gravitational scattering of strings, a thought-experiment for understanding string theory’s version of quantum gravity. This work originated from one of his periodic visits to the CERN TH division and involved, besides Marcello, Daniele Amati and myself.

The so-called ACV collaboration carried on until 2007 (with long visits by Marcello at CERN in 1995 and 2001), but my own collaboration with Marcello continued until 2018, when his health started deteriorating. More recently, the techniques used for this “academic” problem turned out to be relevant for describing real black-hole mergers and the ensuing gravitational radiation.

I had the great privilege of working with Marcello on many occasions throughout his career. His deep knowledge of physics and his passion were only matched by his amazing technical skills. He had set very demanding standards for himself and pursued them with great intellectual honesty and much generosity towards his students and collaborators. His passing is a big loss for our community.

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Bikash Sinha was born on 16 June 1945 in Kandi, Murshidabad in the state of West Bengal, India. After graduating in physics from Presidency College, Kolkata in 1964, he went to the UK where he completed the natural sciences Tripos course at King’s College, Cambridge in 1967, and then gained a PhD in nuclear physics from the University of London in 1970. He returned to India on invitation from nuclear physicist Raja Ramanna and joined the Bhabha Atomic Research Centre (BARC) in 1976.

In the early 1980s Bikash started working in high-energy physics, particularly relativistic heavy-ion collisions and the formation of quark–gluon plasma. He was appointed director of the Variable Energy Cyclotron Centre in 1987 and held concurrent charge as director of Saha Institute of Nuclear Physics from 1992 to 2009. He received numerous awards and honours, including the Padma Shri Award in 2001 and the Padma Bhusan Award (the third-highest civilian award in the Republic of India) in 2010 for his significant contributions to science and technology. He had also been a member of the scientific advisory council to the Indian prime minister.

As the director of two major institutes in Kolkata, Bikash promoted research in different fields of science. In nuclear and particle physics, his efforts put India on the global map, and he was a strong supporter of the engagement of India with the international community via programmes at CERN. Early on, he broke through scientific bureaucracy to press the need for a multi-agency funding model for the nascent collaborations taking shape for the SPS WA93/WA98 experiments. Subsequently, India’s contributions expanded to the LHC, to RHIC at Brookhaven National Laboratory, and then to FAIR at GSI in Germany.

From modest beginnings in the early 1990s – armed with only a handful of collaborators, students and borrowed equipment, but a grand vision and unbeatable spirit – Bikash nourished and led the Indian team to become a major pillar of ALICE, and of heavy-ion physics more broadly. He embraced every challenge, be it the MANAS chip for the large muon chambers or the photon multiplicity detector, made possible on account of his generous attitude in promoting talents and giving chances to youngsters.

As an individual, Bikash was a synthesis of science, culture, philosophy and society. He initiated the medical cyclotron in Kolkata for the diagnosis and treatment of prostate cancer, and was inspired by the works of the great Indian poet and Nobel Laureate Rabindranath Tagore. In May 2022 he fused his passions for science and art in a one-of-a-kind international conference Microcosmos, Macrocosmos, Accelerator and Philosophy (CERN Courier July/August 2023 p22).

In 1988 Bikash initiated a very successful international conference series on the Physics and Astrophysics of Quark Gluon Plasma, and in 2008 he organised and chaired the annual Quark Matter conference in 2008 held in Jaipur, India. Along the way, his efforts paved the way for India to become one of the most prominent non-member-state participants at CERN, culminating in its accession to associate member in 2017.

While the passing of Bikash leaves an undeniable void, his legacy is a vibrant and thriving team that is primed to continue the journey he embarked upon. We will always remember him for his charismatic personality, great kindness, openness and generosity. We honour his memory, and with deepest condolences we extend our sympathy to his family.

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Electrical engineer Philippe Bernard, who made notable technical and managerial contributions across the various sectors at CERN in which he worked, passed away on 10 October 2023.

Born in 1935, Philippe completed his studies at the prestigious Ecole supérieure d’éléctricité in 1956. He began working at CERN in 1962 as engineer-in-charge of the Proton Synchrotron. He went on to design and develop radio-frequency (RF) separators, making substantial contributions to the improvement of these devices that provide well-selected secondary beams. This was particularly important in the early 1970s for experiments with the CERN 2 m hydrogen chamber, the Saclay-built Mirabelle chamber at Serpukhov, and the Big European Bubble Chamber at CERN.

Realising the potential of superconductivity for RF structures, Philippe, together with Herbert Lengeler, was entrusted by CERN Director-General John Adams to develop RF cavities for CERN accelerators in 1978. A vigorous programme with international participation led to the development of five-cell cavities, first made of pure niobium and, later, of niobium sputtered on the more stable copper-substrate to produce robust cavities. This allowed accelerating fields of up to 7 MV/m to be reached.

After tests of prototypes at PETRA (DESY) and the Super Proton Synchrotron, 320 such cavities were produced for the Large Electron-Positron collider (LEP) using niobium-film technology. In the framework of the LEP2 upgrade programme, which started in 1987, these cavities were gradually added to the complement of normal-conducting cavities, which were partially replaced. This enabled an increase in the electron and positron beam energy from 46 GeV in 1989 to 104 GeV by 2000. In addition to this successful development, in the late 1990s Philippe took a strong interest in the design and development of a system of coupled superconducting cavities as a sensitive detector of gravitational waves.

Philippe was also involved in numerous CERN-wide activities, including chairing the purchasing policy monitoring board and serving as president of the CERN health insurance scheme (CHIS). He also served as president and vice-president of the CERN Pensioners’ Association during a critical period.

His open mind, his wide-ranging views and his solid technical knowledge made Philippe a recognised leader. His critical and thoughtful attitude made him a respected discussion partner for the CERN management. Philippe’s commitment to CHIS and to long-term improvements in the social conditions of CERN and ESO staff was widely appreciated and acknowledged. We remember him as a generous, witty and vivacious friend.

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The congress started with parallel meetings on LHC physics, astroparticle physics, nuclear physics and theoretical physics. Two extra sessions were held, one covering technology transfer and the other discussing instrumentation R&D aimed at supporting the HL-LHC, future Higgs factories, and other developments in line with the European strategy for particle physics. The opening ceremony was followed by a lecture by Manuel Aguilar (CIEMAT), who gave an overview of the past 50 years of research in high-energy physics in Spain and the IMFP series. The first edition, held in Formigal (Spanish Pyrenees) in February 1973, was of great significance given the withdrawal of Spain from CERN in 1969, which put high-energy physics in Spain in a precarious position. The participation of prestigious foreign scientists in the first and subsequent editions undoubtedly contributed to the return of Spain to CERN in 1983.

LHC physics was one of the central themes of the event, in particular the first results from Run 3 as well as improvements in theoretical precision and Spain’s contribution to the HL-LHC upgrades. Other discussions and presentations focused on the search for new physics and especially dark-matter candidates, as well as new technologies such as quantum sensors. The conference also reviewed the status of studies related to neutrino oscillations and mass measurements, as well as searches for neutrinoless double beta decay and high-energy neutrinos in astrophysics. Results from gamma-ray and gravitational-wave observatories were discussed, as well as prospects for future experiments.

The programme included plenary sessions devoted to nuclear physics (such as the use of quantum computing to study the formation of nuclei), QCD studies in collisions of very high-energy heavy ions and in neutron stars, and nuclear reactions in storage rings. New technologies applied in nuclear and high-energy physics and their most relevant applications, especially in medical physics, complemented the programme alongside an overview of observational cosmology.

Roundtable discussions focused on grants offered by the European Research Council, R&D strategies and, following a clear presentation of the perspectives of future accelerators by ECFA chair Karl Jacobs (University of Freiburg), possible Spanish strategies for future projects with the participation of industry representatives. The congress also covered science policy, with the participation of the national programme manager Pilar Hernández (University of Valencia).

Prior to the opening of the conference, 170 students from various schools in Cantabria were welcomed to take part in an outreach activity “A morning among scientists” organised by IFCA and CPAN, while Álvaro de Rújula (University of Boston) gave a public talk on artificial intelligence. Finally, an excellent presentation by Antonio Pich (University of Valencia) on open questions in high-energy physics brought the conference to a close.

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Experimental particle physicist Lawrence W Jones, a well-respected mentor and educator who contributed to important developments in accelerators and detectors, passed away on 30 June 2023.

Born in Evanston, Illinois on 16 November 1925, he enrolled at Northwestern University in autumn 1943 but was drafted into the US army a few months later. He served in Europe during World War II in 1944 and 1945, returning to Northwestern to complete a BSc in zoology and physics in 1948, followed by an MSc in 1949. After completing a PhD from the University of California, Berkeley in 1952, Jones went to the University of Michigan to begin a lifetime career in the physics faculty. In 1962 he acted as dissertation adviser to future Nobel laureate Samuel Ting and was promoted to full professor in 1963. He served as the physics department chair from 1982 to 1987 and was named professor emeritus in 1998.

Jones collaborated in the 1950s in the Midwestern Universities Research Association, a collaboration of US universities that developed key concepts for colliding beams, and built the first fixed-focus alternating gradient accelerator. Over the course of his career, Jones also contributed to the development of scintillation counters, optical spark chambers and hadron calorimeters. He participated in experiments designed to measure inelastic and elastic scattering, particle production, dimuon events, neutrino physics and charm production.

Jones came to CERN as a Ford Foundation Fellow (1961–1962) and as a Guggenheim Fellow (1964–1965), and then contributed to cosmic-ray experiments on Mount Evans, Colorado and nearby Echo Lake. In 1983 he joined the L3 experiment at LEP, which was led by his former student Ting. The Michigan team, led by Byron Roe, helped to design, construct and install the experiment’s hadron calorimeter – a key component used to determine the number of elementary neutrino families. Jones also contributed to the construction of L3 cosmics, a programme to trigger on and measure cosmic rays using the detector’s precision muon detector and surrounding solenoidal magnet.

Jones’ interest in entomology led to a species of beetle (Cryptorhinula jonsi) being named after him. On the first Earth Day, in 1970, Jones introduced the term “liquid hydrogen fuel economy” and, in 1976, he joined the advisory board of the International Association for Hydrogen Energy. He had a long involvement with the Ann Arbor Ecology Center, which he led in 1974–1975, and became co-chair of the Michigan Environmental Council’s Science Advisory Committee in 2000.

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Inspired by CERN

It was during this time that Matteo visited CERN. The experience left him with a strong desire to work there but he felt it was an unattainable ambition. Nevertheless, in 2011 he applied for a position through the “Volontaires Internationaux” programme and was successful. He joined the physics department in 2012 as a fellow, testing commercial equipment used in the backend electronics for CERN experiments. A year later he obtained a staff contract with increased responsibilities, including managing a team of around five and hiring people. Making use of CERN’s internal mobility programme, he then joined the electrical power converter group in the technology department and spent six years working with a multicultural team of 15 people. “CERN is the greatest example of a united Europe, as the incarnation of teamwork no matter what language or nationality,” he says, adding that his experience has undoubtedly affected his personality. “It left me with the sensation that I can no longer be in an environment that is not diverse.”

Finally, in 2018, the knowledge that Matteo had acquired at CERN enabled him to realise his teenage ambition, and he built his own synthesiser: the “tiny synth”, based on field programmable gate arrays (FPGAs). At the time, there were no other products on the market using this technology. Subsequently, he was contacted by the CEO of the organisation he works for today, who was looking for an engineer. Matteo was not ready to leave CERN so he asked the human resources department if he could work as a contractor alongside his job. The request was accepted as there was no conflict of interest.

Invest time in acquiring the skills relevant for your sector, but don’t forget to also spend some time thinking about where you are going

Four years into his dual role, however, Matteo began to reconsider his position. He wanted a job more centred on managing people, in the private sector and that was more focused on profitability. “I was very confident in my work, and I also appreciated my colleagues, but at the same time I think I had reached a ‘plateau’ of knowledge, so I felt I was not able to move forward.” Initially, he struggled with the decision whether to leave CERN. He turned to the CERN Alumni Network to find members who had held indefinite contracts at CERN but chose to pursue a career elsewhere. He met with three such people who took the time to listen and share their experiences, but it was a conversation with a colleague that brought him to the realisation that he needed a change. “One of my best friends asked me ‘are you happy?’ and I was not able to answer.”

Matteo left CERN in 2020 after eight enjoyable years, forever grateful of what it taught him. He is now based in Bari, Italy, where he works with people from around the world as an innovation leader at Music Tribe, delivering audio products for DJs and music producers.

As for his advice to others: “Invest time in acquiring the necessary skills relevant for your sector, but don’t forget to also spend some time thinking about where you are going. I was working all the time, developing electronics. But I forgot to ask myself if I am in the right place doing the right thing. We should all spend some time not only working, but on introspection.”

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Maria Fidecaro, an experimental physicist who joined CERN in 1957, passed away on 17 September. Maria was a familiar face to the CERN community until long into her retirement, often seen arm-in-arm with her husband Giuseppe as they made their way through the CERN corridors. She was also well-known to CERN visitors, featuring prominently in the Synchrocyclotron exhibition’s film.

Born in Rome in 1930, Maria completed her university studies at La Sapienza in 1951. There she met Giuseppe, and the pair studied cosmic rays at the Tête Grise laboratory located on the Matterhorn. In 1954 she obtained a fellowship from the International Federation of University Women and joined her future husband at the University of Liverpool developing techniques and experiments for the Synchrocyclotron, CERN’s first accelerator.

In summer 1956 the couple moved to Geneva, joining only a few hundred people at CERN, which had been established just two years earlier. Maria obtained a CERN fellowship in 1957 and began working in a team of three that was developing a novel method to provide polarised proton beams at the Synchrocyclotron – techniques that she would later adapt to carry out polarisation experiments at the Proton Synchrotron and the Super Proton Synchrotron (SPS). She remained at CERN for the rest of her career, where her early research interests included charge–exchange nucleon–nucleon scattering and proton–proton elastic scattering.

In the 1980s Maria participated in the WA78 experiment at the SPS, which was dedicated to the production of bb pairs. She then worked on detectors and analysis for the CPLEAR experiment, which was designed to enable precision measurements of CP, T and CPT violation in the neutral kaon system. She designed and led the construction of a high-granularity electromagnetic calorimeter, helping CPLEAR to achieve new levels of precision in the study of fundamental symmetries.

From 1991 to 1995 Maria was group leader of the CPL group in the Particle Physics Experiments division. She also took part in the NA48/2 experiment, searching for CP violation in the decay of charged kaons, and contributed to the early phases of NA62.

Maria celebrated her retirement in 1995, but continued her work at CERN as an honorary member of the personnel. She had a reserved attitude in all circumstances and a deep sense of duty to the community. As Maria explained in an interview in 2012, “every day or every week there is something new connected with our old work”.

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Theoretical physicist Michel Gaudin, known for his influential works in the domain of integrable models, passed away on 4 August. Michel entered L’Ecole Polytechnique in 1951 and obtained his PhD in 1967 at the Université de Paris. In his PhD thesis he found a solution, given simultaneously in the famous paper by C N Yang, to the Fermi gas with delta-function interaction, introducing what was later called the nested or higher-level Bethe ansatz. Except for a year spent visiting Yang at Stony Brook in 1970, he spent all his scientific life at the fundamental research division of the Commissariat de l’Energie Atomique (CEA-Saclay).

Michel used only French as a scientific language and a significant part of his research remained unpublished. The publication of his book La fonction d’onde de Bethe in 1983 was thus a major event, remaining an inspiring and pedagogical source of a variety of original information that cannot be found anywhere else. Translated into Russian in 1987 and English in 2013, it is considered a classic in the field.

One of the most well-known of his findings is the so-called Gaudin determinant for the norm of the Bethe eigenstates, which now plays a fundamental role in the computation of correlation functions. In another essential work, following the method of C N Yang and C P Yang, Michel solved the thermodynamics of the Heisenberg–Ising ring, simultaneously with Takahashi. He also diagonalised a class of quadratic Hamiltonians in spin variables, now referred to as the Gaudin model, and considered various extensions, in particular a system comprising a single oscillator coupled to a collection of independent two-level atoms, which has become a classic in the cold-atom and Bardeen–Cooper–Schrieffer communities. In addition, his pioneering early works on random matrices with M L Mehta introduced elegant and powerful new methods that played a key role in many developments in random matrix theory, with applications ranging from nuclear physics to non-critical string theories.

An original and prolific personality, Michel was principally guided by a quest for elegance. Although he cared little for recognition, in 2019 he was awarded the prestigious Dannie Heineman Prize for Mathematical Physics.

Michel Gaudin was a man of high integrity and modesty whose life was completely devoted to science. He was known for his rigour and reclusive style of work, but when approached by his colleagues, he generously shared his knowledge and insights.

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On 14 June, Roman Jackiw, one of the most brilliant and profound theorists of his generation, passed away at the age of 83.

Roman Jackiw graduated from Cornell University in 1966 under the supervision of Ken Wilson, moving to Harvard as a junior fellow until 1969. Thereafter, he was a member of the Centre for Theoretical Physics at MIT. Having myself been a postdoc at MIT from 1968 to 1972, we got to know each other well and kept in touch since.

During the Harvard period, while visiting CERN, he wrote, together with John Bell, what is arguably his most famous paper. It became known as the Adler–Bell–Jackiw (ABJ) anomaly. Here “anomaly” stands for a symmetry that, while classically exact, is broken by quantum mechanical effects. This breaking makes it possible for the neutral pion to decay, as observed, into two photons. Another version of the ABJ anomaly, in the context of the strong interaction, provides a solution of the so-called U(1) problem: the absence of a ninth light pseudoscalar meson besides the π, K and η. Indeed, the relatively heavy η′ meson gets most of its mass through the ABJ anomaly and some topologically non-trivial gauge-field configurations.

Later, together with Claudio Rebbi of Boston University, Jackiw introduced the concept of theta-vacua in quantum chromodynamics by which the strong interaction, because of the above-mentioned non-trivial topology, depends on a somewhat hidden angular parameter, θ. Unless vanishing, the θ parameter introduces violations of time-reversal symmetry and, consequently, an electric dipole moment of the neutron for which very strong experimental upper bounds exist.

Interestingly, the combination of these two remarkable contributions by Jackiw imply what is perhaps the only serious theoretical tension facing the Standard Model today. Its resolution calls for the existence of a new particle, the axion, which turns out to also be an interesting candidate for explaining the dark-matter content of the universe.

Roman Jackiw made many other important contributions to the theory of fundamental interactions. One that gained lots of attention now goes under the name of Jackiw–
Teitelboim (JK) gravity, a two-dimensional version of general relativity that can be used as a simple theoretical laboratory for addressing several conceptual problems also occurring in the real world. Another pioneering contribution is the discovery (again with Claudio Rebbi) that fractional charges and spins are easily generated in field theories of interest to condensed-matter physics. Quasiparticles with such properties have indeed been “seen” experimentally.

Jackiw received much recognition for his work: among these the prestigious Dannie Heineman Prize for Mathematical Physics of the American Physical Society and the Dirac Medal of the International Center for Theoretical Physics in Italy.

Since the time of his work with John Bell, Jackiw was very attached to CERN and to the theoretical division/department. It was always a pleasure listening to his clear and inspiring talks while benefitting from his willingness to share – with scientific assurance but also much modesty – his deep ideas about quantum field theory. In one such occasion he told me: “you know, proving an exact result is like having a deposit in a bank: it keeps giving you interest forever”. He was certainly aware of the importance of his contributions to theoretical physics but never boasted too much about them.

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What has been your career trajectory so far?

I completed my PhD at the University of Tokyo (U-Tokyo) in 1995 on precise measurements of the orthopositronium decay rate, in which I solved the problem of the orthopositronium lifetime puzzle. The measurement ultimately confirmed second-order QED predictions with an accuracy of 100 ppm, and positronium’s hyperfine structure and Bose–Einstein condensation are ongoing projects in the Tokyo group. I remained at U-Tokyo as an assistant, associate and then full professor, and in 1995 I joined the OPAL experiment at LEP and then ATLAS at the LHC. At OPAL I took an initiative in electroweak gaugino searches and performed a new search for scalar top quarks. I continued to work on supersymmetry searches at ATLAS, and also made a contribution to the discovery of the Higgs boson. From 2017, I became director of the International Center for Elementary Particle Physics at U-Tokyo, and on 31 March 2024 I will leave the university after close to 40 years to take up my new role at KEK.

How does it feel to be taking over as KEK director general, and what will be your priorities in the coming years?

I am honoured and feel a sense of humility at the same time. We are at a critical time to determine future project(s), and strong international collaborations are crucial. I want to have fun and do my best! The successful accomplishment of ongoing programmes (SuperKEKB, J-PARC upgrade and Hyper-Kamiokande) is the top priority in the coming years. KEK also has photon factories, and upgrades to these are urgent. The International Linear Collider (ILC) is the top priority after SuperKEKB and the construction of Hyper-Kamiokande (Hyper-K).

Will you still play a role in ATLAS?

Personally, I will leave the ATLAS experiment. I thank all ATLAS collaborators with whom I have had a wonderful and exciting time for more than 20 years. Japan has contributed to the HL-LHC projects and the associated ATLAS upgrades, as it did for the first phase of LHC/ATLAS. Now we begin an additional contribution to HL-LHC concerning the power supply for the quench heater and radio-frequency generators for the crab cavities. The Japanese high-energy physics community and MEXT (Ministry of Education, Culture, Sports, Science and Technology) would like to continue their large contributions to CERN, the LHC and ATLAS.

How is data collection progressing at SuperKEKB, and what are the current luminosity targets?

SuperKEKB represents a new generation of electron–positron colliders based on nanobeam technology. The highest instantaneous luminosity achieved so far (5 × 10³⁴ cm^–2 s^–1, a record for an e⁺e^– machine) was obtained with only half the beam current of its predecessor KEKB. Now, SuperKEKB is emerging from a long shutdown and will restart in December. The first target is to reach higher than 10³⁵ cm^–2 s^–1 with the nominal beam current, after which the beam will be squeezed further to reach a final target that is a factor of 10 higher. SuperKEKB opens up opportunities for the discovery of a new CP phase and phenomena beyond the Standard Model. Many new baryon and meson states will be discovered, and a deep understanding of QCD at low energy will be obtained.

What is the current situation with the ILC, and do you expect any advances in the near future regarding Japan’s hosting of the facility?

The Japanese community considers the ILC as the top-priority project after SuperKEKB and the neutrino CP-violation programme at Hyper-K. We would like to realise the ILC as a “global project” built up through a worldwide collaborative effort in which all decisions (such as the construction decision itself, cost sharing, the construction location, risk management and organisation scheme) are taken collectively by all partners from the beginning. This is a new approach in particle physics. We are setting up the ILC technology network and a global discussion framework in collaboration with the IDT (the International Development Team established by the International Committee for Future Accelerators).

Moving to neutrinos, how are things going with the T2K upgrade and Hyper-K projects, and how strongly do these relate to LBNF/DUNE in the US?

A megawatt power-upgrade of the drive accelerator at J-PARC and the construction of the Hyper-K detector are ongoing without any serious problems. We expect to start the neutrino programme with Hyper-K in 2027, with the main goal of establishing the CP phase in the neutrino sector. We have much experience with T2K and water Cherenkov detectors, which are an advantage for this programme. We can also share our experience of the target of the high-power proton beam with LBNF. DUNE and Hyper-K are quite different detectors, so we can cover each other.

What are KEK’s major collaborations in the broader region, for example JUNO and the Super Charm-Tau factory?

These are very interesting programmes. The Japanese high-energy physics community has contributed to many ongoing programmes overseas, and we also have many important projects in Japan. Human resources are limited and focussing on these ongoing programmes is the priority.

The SuperKEKB and neutrino programmes, in addition to the muon programmes in Japan, always open a window for the world. New collaborators are always welcome to these programmes. As for involvement in other proposed future-collider projects, for example FCC and CEPC, it depends on the realisation of the ILC and the collaboration frameworks that will be proposed.

How do you view the current global picture of high-energy physics?

My happy time as a scientist in OPAL and with ATLAS, and the enormous success of LEP and the LHC prove that international collaboration is very successful in our field. I am afraid that our next major project has become too large and will cost more than one country can afford, which is why we need the ILC to be a global project. I understand that this approach will not be easy, but we have fantastic experience to build on. Now we face problems in international relations generally, such as war, pandemics and budget tensions in many counties. We can overcome them, I hope.

The post The future is international appeared first on CERN Courier.

Like many of my colleagues, I have always devoted a significant fraction of my time to share my passion for the field with diverse audiences. Society funds our research, so we have a fundamental duty to report back about our discoveries, act as an advocate for science in general, and educate and inspire the next generation. Doing outreach is not only enjoyable but also a valuable exercise that forces you to look at your own work from an outside perspective and to adapt your story for different audiences. Given the collective responsibility of particle physicists for garnering societal support for fundamental science, one might expect the entire field to support individuals involved in outreach activities. Regrettably, this is not always the case.

A new programme at the Leiden Institute of Physics, in collaboration with colleagues from the science communication research group, is investigating how we approach physics communication. When studying our attitudes, certain “points of attention” become rapidly apparent.

Critical points

One concerns cultural appreciation and the role of the scientist. Outreach is often still perceived as something someone does in their spare time and not a valuable activity for “serious” scientists. Many young researchers are all too aware of this attitude, and given the limited number of permanent positions and the emphasis on leadership roles and scientific output for career advancement, outreach often gets reduced priority. This means we’re missing out on an enormous potential of energy and ideas to connect with society. It is important that scientists realise that good communication skills are indispensable for an academic career, which, after all, includes teaching and grant writing. While professional communicators do great work, it’s crucial that more physicists are directly involved as they inherently radiate their passion and drive.

A second point is public relations versus the role of science in society. While every country can simultaneously benefit from new discoveries, communication departments within universities and research institutes – including CERN – often struggle to move beyond the frame of public relations and the latest scientific breakthroughs. In doing so, there is an increasing tendency to project a polished image and to be too self-focused while neglecting opportunities to provide insights into laboratory life – including failure, which is an inevitable aspect of the scientific process – and the stories behind the publications.

Impact assessment is a third factor where we could do better. Despite the increasing encouragement from funding agencies to make societal engagement an integral component of research proposals, we frequently fall short when it comes to conducting impact assessments. While researchers invest years in writing academic papers and scrutinise collaborators for failing to cite the most recent articles, we seem perfectly happy to ignore the literature on science-communication research and input from experts when developing outreach initiatives. Moreover, owing to our lack of collective memory, we do not have a systematic way to learn from good and bad practices.

Last but not least, developing effective communication skills is also critical in peer-to-peer interactions. We don’t often talk about it openly, but it is remarkable how physicists perpetuate the poor quality of presentations and seemingly endless meetings, and how increasingly challenging it is to understand developments in other sub-fields. With proper attention given to our internal communication, we would all stand to benefit significantly.

A change in culture does not happen overnight. Nevertheless, given the ongoing discussions about the future of the field, for example about a future collider at CERN, it is vital that we develop a stronger, broader and especially more open science communication strategy. It should be centred around curiosity and the amazing people in our field, as that is how we can connect with society to start a dialogue, while at the same time finding ways to support and acknowledge the work of colleagues who engage in outreach activities. Particle physics is a wonderful adventure. Let’s make sure the world knows about it.

The post Time for an upgrade appeared first on CERN Courier.

CERN has traditionally tailored education and outreach material predominantly towards high-school students, in particular those already expressing an interest in science.  For this age group, it is relatively easy to find overlaps between school curricula and work at CERN. Such visitors will continue to find engaging content in our exhibitions. However, if CERN is to connect to a broader section of the public and attract a more diverse cohort of future scientists, it needs to reach out beyond existing science fans, attracting younger audiences before stereotypes set in.

Positive contacts

Over the decades, communication best-practice has evolved from the idea that to inspire children to choose a career in science, you just need to make it sound interesting. Now, it is recognised that there are multiple factors influencing choice. The Aspires research project at University College London, for example, has highlighted the importance of “science capital”, a notion based on the variety of positive contacts with science that children experience. This includes knowing people who work in science, talking with family and friends, doing science-based activities outside school and there being a generally positive attitude towards science within the family setting.

At schools, careers information often comes once choices to drop science subjects have already been made. And without role models to identify with, or contact with science or science-related professions through family and friends, it can be extremely difficult for some students to imagine themselves as future scientists. Hence the drop in pupils expressing such aspirations from the end of primary education onwards that occurs in many countries. By offering younger students the opportunity to experiment and play in a scientific environment, Science Gateway seeks to counter this drop. In addition to the existing science-fan visitors, it aims to reach those with less science capital at home, so that children can discover new opportunities.

There is a slogan in the exhibitions world: “hands on, minds on”. A good exhibit creates memorable experiences that empower visitors to explore and engage, rather than simply transmitting knowledge in a unidirectional way. Science Gateway offers activities – such as designing a detector or collaborating to lower equipment into a cavern – where children are encouraged to think logically, and exhibits that encourage them to make their own deductions, helping them to become more confident that science is for them. Here the exhibition guides play a key role in encouraging interaction and play.

Sometimes in a hands-on science centre, one can have the impression that children are having so much fun racing from exhibit to exhibit that there is no valid experience. This is countered by research which shows that learning comes in a broad variety of forms. Informal learning experiences, such as those at Science Gateway, can have just as much impact as in-school learning.

The exhibitions offer a variety of different environments – playful areas and beautiful spaces, including artworks, that can be enjoyed by simply sitting back and reflecting.  The exhibitions team has also collaborated with community groups to develop tactile content and ensure the exhibits are accessible to wheelchair users. Not all exhibits will be accessible for younger children, or for the visually impaired, but throughout there is a spread of different experiences that give something for everyone to enjoy.

The ambition is for CERN to become a popular destination for a fun day out, attracting a broad section of the public, both those who might one day become scientists themselves and those who might never choose that path, but who are curious to explore the new buildings that have popped up in their local area. Successful outcomes can be as simple as visitors having fun in a scientific environment. This is a first step towards being open to scientific ideas and methods – a valid goal in today’s world of misinformation and distrust, where science is sometimes talked of as something you might or might not choose to believe in.

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Born in Liège, Belgium in 1935, Oscar joined CERN in 1961, working initially in the Proton Synchrotron (PS) radio-frequency (RF) group. At the time, the PS beam intensity was still below 10⁹ protons per pulse and the beam-control system was somewhat difficult to master, even though the operations consisted mainly of striking internal targets at 24 GeV/c. The control system became increasingly complex when the PS slow-resonant extraction system of Hugh Hereward was put into service. As part of a team of expert accelerator physicists that included Dieter Möhl, Werner Hardt, Pierre Lefèvre and Aymar Sörensen, Oscar wrote a substantial FORTRAN simulation program to understand how the extraction efficiency depended on its numerous correlated parameters.

In the 1970s, the PS division set out to digitise the controls of all PS subsystems (Linac, PS Booster, RF, beam transport systems, vacuum system, beam observation, etc). These subsystems used independent control systems, which were based on different computers or operated manually. Oscar was tasked with devising a structured naming scheme for all the components of the PS complex. After producing several versions, in collaboration with all the experts, the fourth iteration of his proposed scheme was adopted in 1977. To design the scheme, Oscar used the detailed knowledge he had acquired of the accelerator systems and their control needs. His respectful and friendly but tenacious way with colleagues enabled him to explore their desires and problems, which he was then able to reconcile with the needs of the automated controls. Oscar was modest. In the acknowledgements of his naming scheme, he wrote: “This proposal is the result of numerous contributions and suggestions from the many members of the division who were interested in this problem and the author is only responsible for the inconsistencies that remain.”

On Giorgio Brianti’s initiative, following the interest of the CERN Council’s finance committee, the “Bureau de Liaison pour l’Industrie et la Technologie” (BLIT) was founded, with Oscar in charge. His activity began in 1974 and ended on his retirement in 1997. His approach to this new task was typical of his and CERN’s collaborative style: low-key and constructive. He was eager to inform himself of details and he had a talent for explaining technical aspects to others. It helped that he was well educated with broad interests in people, science, technology, languages along with cultural and societal purposes. He built a network of people who helped him and whom he convinced of the relevance of sharing technological insights beyond CERN.

After more than 20 years developing this area, he summarised the activities, successes and obstacles in Technology Transfer from Particle Physics, the CERN Experience 1974–1997. When activities began in the 1970s, few considered the usefulness of CERN technologies outside particle physics as a relevant objective. Now, CERN prominently showcases its impact on society. After his retirement, Oscar continued to be interested in CERN technology-transfer, and in 2012 he became a founding member of the international Thorium Energy Committee (iThEC), promoting R&D in thorium energy technologies.

No doubt, Oscar is the pioneer of what is now known as knowledge-transfer at CERN.

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Henri Navelet died on 3 July 2023 in Bordeaux, at the age of 84. Born on 28 October 1938, he studied at the École Normale Supérieure in Paris. He went on to become a specialist in strong interactions and was a leading member of the Service de Physique Théorique (SPhT, now Institut de Physique Théorique) of CEA Saclay since its creation in 1963. Henri stood out for his theoretical rigour and remarkable computational skills, which meant a great deal to his many collaborators.

In the 1960s, Henri was a member of the famous “CoMoNav” trio with two other SPhT researchers, Gilles Cohen-Tannoudji and André Morel. The trio was famous in particular for introducing the so-called Regge-pole absorption model into the phenomenology of high-energy (at the time!) strong interactions. This model was used by many physicists to untangle the multitude of reactions studied at CERN. Henri’s other noteworthy contributions include his work with Alfred H Mueller on very-high-energy particle jets, today commonly referred to as “Mueller-Navelet jets”, which are still the subject of experimental research and theoretical calculations in quantum chromodynamics.

Henri had a great sense of humour and human qualities that were highly motivating for his colleagues and the young researchers who met him during his long career. He was not only a great theoretical physicist, but also a passionate sportsman, training the younger generations. In particular, he ran the marathon in two hours, 59 minutes and 59 seconds. A valued researcher and friend has left us.

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Roger began his career with a doctorate in experimental particle physics from the University of Sheffield in 1979, going on to a postdoctoral position at the Rutherford Appleton Laboratory until 1983. Throughout this time, he worked on experiments at CERN’s Super Proton Synchrotron (SPS) and was based at CERN from 1977. In 1983 he joined the SPS operations group, where he was responsible for accelerator operations until 1989. Roger then moved to the Large Electron Positron collider (LEP), coordinating the team’s efforts through the commissioning phase and subsequent operation, and became operations group leader in the late 1990s.

After LEP shut down in 2000, Roger became progressively more involved in the Large Hadron Collider (LHC), planning and building the team for commissioning with beam. He then took a leading role in the LHC’s early operation, helping to push the LHC’s performance to Higgs-discovery levels before becoming director of the CERN Accelerator School, sharing his wealth of experience and inspiring new generations of accelerator physicists.

Those of us who worked with Rog invariably counted him as a friend: it made perfect sense, given his calm confidence, his kindness and his generosity of spirit. He was straightforward but never outspoken and his well-developed common sense and pragmatism were combined with a subtle and wicked deadpan sense of humour. We had a lot of fun over the years in what were amazing times for CERN. Looking back, things he said, and did, can still make us chuckle, even in the sadness of his untimely passing. Rog had a passionate, playful eye for life’s potential and he wasn’t shy. There was an adventurous spirit at work, be it in the mountains or the streets of New York, Berlin or Chicago. His specialities were tracking down music and talking amiably to anyone.

During a service to celebrate Roger’s life on 16 June, a poem of his called It’s a Wrap was read by his daughter Ellie, revealing a physicist’s philosophical view on life and the universe. Two of his favourite quotes were on the order of service: Mae West’s “You only live once, but if you do it right, once is enough” and Einstein’s “Our death is not an end if we can live on in our children and the younger generation. For they are us, our bodies are only wilted leaves on the tree of life.” Another, by Hunter S Thompson, was mentioned in a homage given by his son, Rob: “Life should not be a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside in a cloud of smoke, thoroughly used up, totally worn out, and loudly proclaiming “Wow! What a Ride!” 

Way to go, Rog, way to go.

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“The military is extremely interested in autonomous vehicles,” explains Jack. “But removing the driver from, say, a fleet of tanks, increases the number of breakdowns: many maintenance checks are triggered by the driver noticing, for example, a ‘funny noise on start-up’, or ‘a smell of oil in the cabin’.” Jack worked on trying to replicate this intuition by using very early signs in sensor signals. Such a capability permits high confidence in mission success, he adds. “It also ensures that during a mission, if circumstances change, dynamic asset information is available for reconfiguration.”

Working in defence was “exciting and fast- paced” and enabled Jack to see his research put to practical use – he got to drive a tank and attend firing tests on a naval frigate. “It’s especially interesting because the world of defence is something most people don’t have visibility on. Modern warfare is constantly evolving based on technology, but also politics and current affairs, and being on the cusp of that is really fascinating.” It also left him with a wealth of transferrable skills: “Defence is a high-performance world where product failure is not an option. This is hardcoded into the organisation from the bottom up.”

Back to his roots

Growing up in Geneva, CERN always had a mythical status for Jack as the epitome of science and exploration. In 2022 he applied for a senior fellowship. “Just getting interviewed for this fellowship was a huge moment for me,” he says. “I was lucky enough to get interviewed in person, and when I arrived I got a visitor pass with the CERN-logo lanyards attached. Even if I didn’t get the job I was going to frame it, just to remember being interviewed at CERN!”

I love the idea of working on the frontiers of science and human understanding

Jack now works on the “availability challenge” for the proposed Future Circular Collider FCC-ee. Availability is the percentage of scheduled physics days the machine is able to deliver beam, (i.e. is not down for repair). To meet physics goals, this must be 80%. The LHC – the world’s largest and most complex accelerator, but still a factor three smaller and simpler than the FCC – had an availability of 77% during Run 2. “Modern-day energy-frontier particle colliders aren’t built to the availabilities we would need to succeed with the FCC, and that’s without considering  additional technical challenges,” notes Jack. His research aims to break down this problem system by system and find solutions, beginning with the radio frequency (RF). 

On the back of an envelope, he says, the statistics are a concern: “The LHC has 16 superconducting RF cavities, which trip about once every five days. If we scale this up to FCC-ee numbers (136 cavities for the Z-pole energy mode and 1352 for the tt threshold), this becomes problematic. Orders of magnitude greater reliability is required, and that itself is a defining technical challenge.

Jack’s background in defence prepared him well for this task: “Both are systems that cannot afford to fail, and therefore have extremely tight reliability requirements. One hour of down time in the LHC is extremely costly, and the FCC will be no different.”

Mirroring what he did at Babcock, one solution could be fault prediction. Others are robot maintenance, and various hardware solutions to make the RF circuit more reliable. “Generally speaking, I love the idea of working on the frontiers of science and human understanding. I find this exploration extremely exciting, and I’m delighted to be a part of it.”

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Toichiro “Tom” Kinoshita was born in Tokyo and raised in Tottori, the western rural part of Japan. When Tokyo Imperial University (now the University of Tokyo) reopened in 1946 after World War II, he returned to the campus. He was interested in theoretical particle physics, and asked Kunihiko Kodaira, an associate professor of mathematics and physics, to supervise him. He also attended the weekly seminars held by Sin-Itiro Tomonaga, who went on to share the Nobel Prize (with Schwinger and Feynman) for his fundamental work in quantum electrodynamics, QED. Equipped with a strong understanding of the renormalisation of QED from Tomonaga’s group, he began to investigate the renormalisability of charged vector bosons and collaborated with Yoichiro Nambu. Both were accepted by the Institute for Advanced Study at Princeton (IAS) as postdoctoral fellows in 1952. After a two-year stay at IAS, Kinoshita became a postdoc at Columbia University and within a year he was offered a research associate position at Cornell University, where he spent the rest of his career.

In 1966 Kinoshita revisited CERN. During a tour on the first day, a “wiggle plot” posted on the wall captured his gaze. An experiment to measure the anomalous magnetic moment of the muon (muon g-2) at CERN was in progress, and Kinoshita immediately dropped off the tour and rushed to the library to look for the known QED results on charge-renormalisation constants. His earlier study of the mass singularity brought him the inspiration that the leading contribution of the sixth-order term for muon g-2 can be obtained by simply multiplying the already-known quantities. It was the moment he started his life-long quest on the QED calculation of the lepton g-2 values.

After returning to Cornell, he started investigating all the sixth-order QED vertex diagrams. Due to their complexity he chose numerical means to evaluate them, his earlier studies on the three-body variational calculation of the helium atom in the 1950s helping him on his way. The new rules were invented to construct pointwise-subtraction terms for ultraviolet and infrared divergences of a Feynman integral, with which renormalisation could be realised without breaking the gauge symmetry of QED. After the first result came out in 1972, he kept improving the precision of the sixth-order term. His results were used for a quarter of a century to compare the theory to the measurement and to determine the fine-structure constant, among other calculations.

Retired from Cornell University in 1995, Kinoshita was delighted not to have duties other than physics research and started calculating the 10th-order QED contribution to g-2. We joined the 10th-order project in 2004, and his passion was the driving force of our collaboration. He visited RIKEN in Japan every year, and while he was in the US we received an e-mail every morning notifying us of his progress, queries and suggestions. The first entire 10th-order results were published in 2012. His final paper came out in 2019. He wished to be active until he was 100 years old and almost accomplished it.

Tom was always polite and calm, even when physics discussions heated up, and had an inner passion for the pursuit of truth that persisted throughout his life. He is survived by his three daughters and six grandchildren. His wife Masako, a well-known expert in Japanese loop braiding, passed away in 2022. Two diagrams are engraved on their tombstone: a Feynman diagram of QED at 10th order, and a loop-manipulation method. The family also established two undergraduate scholarships at Cornell in their memory.

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“My visit to SESAME on 8 June 2023 has convinced me that Iraq will stand to greatly benefit from membership, and that this would be the right moment for it to become a member,” stated Naeem Alaboodi, minister of higher education and scientific research and head of the Iraqi Atomic Energy Commission, in his letter to Rolf Heuer, president of the SESAME Council. “However, before doing so it would like to better familiarise itself with the governance, procedures and activity of this centre, and feels that the best way of doing this would be by first taking on associate membership.”

SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East), based in Allan, Jordan, was founded on the CERN model and established under the umbrella of UNESCO. It opened its doors to users in 2017, offering third-generation X-ray beamlines for a range of disciplines, with the aim to be the first international Middle-Eastern research institution enabling scientists to collaborate peacefully for the generation of knowledge (CERN Courier January/February 2023 p28). SESAME has eight full members (Cyprus, Egypt, Iran, Israel, Jordan, Pakistan, Palestine and Turkey) and 17 observers, including CERN. One of SESAME’s main focuses is archaeological heritage. This will be the topic of the first Iraqi user study, which involves two Iraqi institutes collaborating in a project of the Natural History Museum in the UK.

Iraq has been following progress at SESAME for some time. As an associate member Iraq will enjoy access to SESAME’s facilities for its national priority projects and more opportunities for international collaboration.“Iraq’s formal association with SESAME will be very useful for Iraqi scientists to gain the required scientific knowledge in many different areas of science and applications using synchrotron radiation,” said Hua Liu, deputy director-general of the International Atomic Energy Agency, which has been actively encouraging its member states located in the region to seek membership of SESAME.

“The Council and all the members of SESAME are delighted by Iraq’s decision,” added Heuer. “We look forward to further countries of the region joining the SESAME family. With more beamlines available in the future, we hope that user groups from different countries will be working together on projects and we will see more transnational collaboration.”

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Stan hardly had a typical childhood. Born in Warsaw, Poland, his youth was dominated by World War II, which caused great hardships, including the separation of his family for several years, followed by a difficult life under the communist regime. Finally, his mother, brother and he managed to escape to Sweden. There, they were refugees for eight months, before they were finally able to move to the US. Stan’s father remained in Poland, where he was jailed for five years, and never received a visa to rejoin his family.

From a very young age, Stan was an exceptional student who loved and excelled at mathematics. He continued to stand out in school in his new country and gained admission to Harvard University as an undergraduate, majoring in physics. He went on to Berkeley as a graduate student in physics, which is where he and I met and became lifelong friends, colleagues and sometimes collaborators.

Upon receiving his PhD in 1962, Stan spent a year at CERN and Collège de France, Paris (1964–1965). He returned frequently to CERN, including for a period supported through a John Simon Guggenheim Fellowship in 1973–1974. During that year, Stan continued his research on the excited states of hadrons made from combinations of quarks. He continued his close association with CERN, once again as a scientific associate in 1980–1981, and for shorter periods throughout his career.

Stan was appointed assistant professor in the physics department at Stanford in 1966, advanced to full professor in 1974, served as chair from 1982–1985 and stayed on the faculty until his retirement in 2015. He characteristically became interested in the newest and most exciting areas in the field, and was quick to join the design effort for the Superconducting Super Collider (SSC). He served as deputy director of the SSC central design group in Berkeley and was deeply involved in proposing and obtaining approval for the construction of the SSC in Texas. He continued to be active in many aspects of the SSC until it was cancelled by Congress in 1993, and wrote an insightful two-volume history of the project.

After the SSC disappointment, Stan characteristically bounced back to take on a new emerging area of particle physics: neutrino masses and oscillations. He proposed and led the MINOS experiment, a key element of a long-baseline neutrino experiment that sent a beam of neutrinos through a near detector at Fermilab and to a second detector, 735 km away, in a deep mine in Minnesota. MINOS was very important in providing evidence confirming the observations of atmospheric neutrino oscillations from Super-Kamiokande in Japan.

Stan received many honours, including the Pontecorvo Prize in 2011 and the APS Panofsky Prize in 2015 for his neutrino work. He met his wife, Esther, while he was a PhD student at Berkeley. They married in 1961 and had three daughters of whom he was very proud, Susan (CEO of YouTube), Janet (professor of paediatrics at UCSF Medical School) and Anne (founder and CEO of 23andMe). He will be very much missed by his many long-time friends and colleagues. 

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Milos began his career in the 1980s on an experiment at the Serpukhov accelerator in the former USSR, investigating proton–antiproton and later deuteron–antideuteron collisions in the Ludmila hydrogen bubble chamber. After obtaining his PhD in 1984, while still at JINR Dubna, he was also involved in the DELPHI experiment at LEP, which played a key role in the Czech Republic’s entry into CERN in 1993. 

After returning to the Institute of Physics, he was at the origin of the participation of Czech physicists in the ATLAS experiment at the LHC, the construction of which was approved in 1994. Together with other staff of the Institute of Physics and colleagues from Charles University, he initiated the construction of the ATLAS TileCal hadron calorimeter and built a laboratory for the assembly and testing of the calorimeter submodules in the former garage of the Institute of Physics. 

Since his participation in the Ludmila and DELPHI experiments, Milos focused on data processing. Already in the mid-1990s, he had built a computer farm for data processing and modelling at the Institute of Physics, which today serves several large experiments. 

In 1997, together with colleagues from Charles University and the Czech Technical University, he initiated the group’s participation in the D0 experiment at the Tevatron, Fermilab. Participation in this experiment was important for the training of young physicists in ATLAS, the construction of which was beginning at that time. After the Tevatron was decommissioned in 2011, Milos obtained funding for the Fermilab–CZ research infrastructure in 2016 with a gradual transition to the neutrino-physics programme. He worked on the NOvA experiment and also used his experience and contacts at CERN for the future DUNE experiment.

The reach of Milos’s work extends far beyond his home institute. Within the Czech Republic, it was the coordination of the activities of Czech institutions in Fermilab and the development of data processing. He was also a long-standing member of the Committee for Cooperation of the Czech Republic with CERN. His international reputation is documented by numerous memberships in steering committees of experiments and projects, and a number of conferences he co-organised. Among the most important are ACAT 2014, CHEP2009, DØ Week 2008 and ATLAS Week 2003.

Milos’s collegiality and friendship will be missed by all of us.

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James Burkett Hartle passed away on 17 May in Zurich at the age of 83. Known as the father of quantum cosmology, Jim made landmark contributions to our understanding of the origin of the universe.

Born in Baltimore, Maryland, Jim obtained his undergraduate degree in physics at Princeton University, where he was mentored by John Wheeler. He attended graduate school at Caltech where he worked under Murray Gell-Mann, earning his PhD in 1964 with a dissertation entitled The complex angular momentum in three-particle potential scattering.

After graduating, Jim briefly taught at Princeton before joining the faculty at the University of California, Santa Barbara (UCSB) in 1966. Excited by the discoveries of pulsars, quasars and the cosmic microwave background radiation, Jim turned away from particle physics. In the late 1960s he wrote a series of influential papers, one with Kip Thorne, on the dynamics of rotating neutron stars. The pair organised regular gatherings between their research groups, which turned into the Pacific Coast Gravity Meetings that still run today.

In 1971 Jim used a Sloan Fellowship to go to the University of Cambridge, where he was immersed in the emerging fields of relativistic astrophysics and cosmology. There he met Stephen Hawking, with whom he developed a remarkable long-term collaboration. Two of their papers became classics: one, in 1976, introduced the Hartle–Hawking quantum state for matter outside a black hole, which is fundamental to black-hole thermodynamics and inspired the so-called Euclidean approach to quantum gravity; the other, in 1983, put forward the Hartle–Hawking “no-boundary” wave function of the universe, showing for the first time how the conditions at the Big Bang could be determined by physical theory.

Except for a brief appointment at the University of Chicago, Jim spent his entire career at UCSB, an environment he found congenial, supportive and inspiring. Jim was a wise and caring mentor to countless young scientists and, though reluctant to venture into the public arena, he also did much to forge a strong physics community. In 1979 he cofounded the Institute for Theoretical Physics (now the Kavli Institute for Theoretical Physics) at Santa Barbara, a mecca for physicists ever since.

The Hartle–Hawking wave function not only revolutionised quantum cosmology but also raised tantalising new questions. Jim began to think more deeply about what it entails to apply quantum mechanics to the universe as a whole. Throughout the 1990s, he and Gell-Mann developed the consistent-histories formulation of quantum mechanics, which clarified the physical nature of the branching process in Everettian quantum mechanics and was sufficiently general to describe single closed systems.

While part of some extraordinary collaborations, Jim was also an independent thinker. About one-third of his publications are beautifully written single-author papers often touching on seemingly intractable questions, far from current fashions and approached with enormous care and open-mindedness. In 2003 Jim published Gravity: An Introduction to Einstein’s General Relativity, a textbook gem with a minimum of new mathematics and a wealth of illustrations that made Einstein’s theory accessible to nearly all physics majors.

Jim retired in 2005, to focus on physics. In 2006 he became an external professor at the Santa Fe Institute, collaborating with Gell-Mann during summer visits. That year also marks the start of my own collaboration with Jim. We took up quantum cosmology again and became immersed in some of the field’s heated debates. Unperturbed, Jim set out the beacons. Often, we would be joined by Hawking, who by then had great difficulties communicating, to flesh out the predictions of the no-boundary wave function. Studying the role of the observer in a quantum universe, we were led to a top-down approach to cosmology in which quantum observations retroactively determine the outcome of the Big Bang, thereby realising an old vision of Wheeler’s.

Few scholars ventured as deeply into the fundamentals of physics as Jim did. A selection of his reflections on the deeper nature of physical theory were published in 2021 in The Quantum Universe: Essays on Quantum Mechanics, Quantum Cosmology, and Physics in General. With characteristic humility, however, Jim reminded us that he didn’t have a philosophical agenda.

Despite suffering the devastations of Alzheimer’s disease, physics remained the driving force in Jim’s life until the very end. Yet his intellectual curiosity stretched much further. He was a polymath and an eclectic reader whose interests ranged from Middle Eastern and Mayan archaeology, to American colonial history, Russian literature and eccentric 19th-century religious female figures. Above all, Jim was an exceptionally generous, wise, humble and gentle man.

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Thesis awards from ALICE

During ALICE Week at CERN from 10-14 July, 2023 the collaboration awarded its annual thesis awards to: Rita Sadek (Subatech/IN2P3; LHCb/LLR Palaiseau) for “MFT (muon forward tracker) commissioning and preparation for Run 3 data analysis with ALICE”; and Luuk Vermunt (Utrecht University; ALICE/GSI) for “Hadronisation of heavy quarks; production measurements of heavy-flavour hadrons from small to large collision systems”. Both defended their theses last year and were picked from 21 other submitted theses.

Success for ATLAS eight

Eight ATLAS PhD students have been announced winners of the collaboration’s 2022 thesis awards: Daniel Camarero Munoz (Universidad Autónoma de Madrid) for “Measurements of the inclusive isolated-photon and photon-plus-jet production in pp collisions at 13 TeV with the ATLAS detector”; Giuseppe Carratta (University of Bologna; INFN) for “Search for Type-III See Saw heavy leptons in leptonic final states using proton-proton collisions at 13 TeV with the ATLAS detector”; Guglielmo Frattari (Sapienza University of Rome; Brandeis University) for “Investigating the nature of dark matter and of the Higgs boson with jets and missing transverse momentum at the LHC”; Maria Mironova (University of Oxford; Berkeley Lab) for “Search for Higgs Boson Decays to Charm Quarks with the ATLAS Experiment and Development of Novel Silicon Pixel Detectors”; Brian Moser (Nikhef; CERN) for “Boson Production at High Energy in Decays to Bottom Quarks and Their Interpretations with the ATLAS Experiment at the LHC”; Giulia Ripellino (KTH Stockholm; Uppsala University) for “Haystacks and Needles – Measuring the number of proton collisions in ATLAS and probing them for the production of new exotic particles”; Bastian Schlag (JGU Mainz; Stanford University) for “Advanced Algorithms and Software for Primary Vertex Reconstruction and Search for Flavor-Violating Supersymmetry with the ATLAS Experiment”; and Emily Anne Thompson (DESY; Berkeley Lab) for “Search for long-lived Supersymmetric particles using displaced vertices with the ATLAS detector at the LHC”.

CMS recognizes theses 

During CMS week (12-16 Jun, 2023) at CERN, the collaboration recognized three PhD students who defended their theses between Nov and Dec 2022 on CMS-related work. Angira Rastogi (IISER Pune; LBNL) did her thesis on “Inclusive nonresonant multilepton probes of new phenomena”, especially focusing on BSM searches and track reconstruction. Writing about “Searches for undiscovered processes using the multi-lepton final state in proton-proton collisions at CMS” Willem Verbeke (Ghent University; Zenseact) looked at unknown processes such as the production of sterile neutrinos, single top-quark production as well as searching for supersymmetry using neural networks. For his PhD David Walter (Hamburg University; CERN) did “First differential measurements of tZq production and luminosity determination using Z boson rates at the LHC”, investigating single top-quark production associated with the Z boson.

LHCb awards for aspiring researchers

On 7 June, the LHCb collaboration honoured PhD students who made exceptional contributions to the collaboration with their theses. Saverio Mariani (Universita di Firenze; CERN) was awarded for his work on fixed-target physics with the LHCb experiment, using proton-helium collision data to understand antiproton production in cosmic rays. Peter Svihra (University of Manchester; CERN) was recognised for detector R&D towards a silicon-pixel detector for the upgraded LHCb detector.

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Massimo Ferrario (INFN, Frascati) is cited for his formidable contributions to high-brightness photoinjectors, free-electron-laser photon sources and plasma-acceleration techniques. Following this path, he currently leads the EuPRAXIA project, which aims to develop the first dedicated research infrastructure based on novel plasma-acceleration concepts.

Lucio Rossi (University of Milan) is recognised for his key role in R&D for large superconducting ultra-high-field magnets, in particular those for the LHC. Rossi also proposed, founded and initially directed the High-Luminosity LHC upgrade based on advanced niobium-tin magnet technology, which is due to enter operations in 2029.

Described as one of the most prolific and creative authors in accelerator physics, and author of seminal discoveries that have made it possible to realise the most modern high-luminosity, high-energy colliders, Frank Zimmermann (CERN) is cited for his fundamental and pioneering contributions to the understanding and modelling of various effects related to accelerated electron beams. His current research contributes to the HL-LHC upgrade and future colliders, such as the proposed Future Circular Collider at CERN.

All three will receive the prize during a presentation at the opening session of the 109^th National Congress of the SIF in Salerno, Italy on 11 September.

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Born in Athens in 1953, Stavros pursued physics at the University of Athens. In 1979 he obtained his speciality doctorate from École polytechnique in Paris. He obtained his PhD at Athens in 1985, and later became an associate professor there (1989–1996). From 1979 to 1982 he spent three years as a postdoc at Fermilab. He also worked at CERN, as a research fellow (1983–1986), research associate (1991–1992) and corresponding fellow (1996). He was then appointed professor at the University Claude Bernard Lyon 1, and in 2004 became a professor at the University Paris VII Denis Diderot (now Université Paris Cité).

From 2002 to 2012 Stavros was deputy scientific director of IN2P3, during which he steered the institute to a leading position in astroparticle physics. He was particularly active in the emerging field of multi-messenger astronomy and in instrumentation. In this context, he played a key role in the creation of the APC laboratory in Paris, of which he was director from 2014 to 2017. Until his death, he led the French–Italian European Gravitational Observatory consortium, coordinating projects related to the detection of gravitational waves with the Virgo observatory.

Stavros’s scientific career was extremely rich, as evidenced by hundreds of publications on topics related to research collaborations, experimental techniques, or the conception and design of new research infrastructures. At CERN, he distinguished himself by developing software for simulating particle interactions, which later became a standard used at LEP. He also played an essential role in federating teams in several large international collaborative projects. One example is his involvement in the OPERA experiment at Gran Sasso laboratory; another is his leading role in the development of underwater neutrino telescopes, starting with the NESTOR project, which led to ANTARES and KM3NeT. 

Over the past 15 years, Stavros played a central role in defining a global strategy in astroparticle physics. With the support of the European Commission, he created ASPERA, followed by the AstroParticle Physics European Consortium, which today gathers about 20 European countries. He was also involved in interdisciplinary research projects, mainly in the field of geosciences. He was co-director of the Laboratory of Excellence UnivEarthS from 2014 to 2018 and at the forefront of a seismometer project to be installed on the Moon.

Stavros was keen to promote science to a wide audience. Since 2015, he was a member of the jury for the Daniel and Nina Carasso Foundation, and in 2019 he organised an exhibition “The Rhythm of Space” at the museo della Grafica in Pisa. He was also coordinator of the European Horizon 2020 project REINFORCE, which intends to support more than 100,000 citizens to increase their awareness of and attitude towards science. 

Stravros was driven by an inexhaustible desire to contribute to the advancement of science by serving, stimulating and animating the community. Steeped in philosophy, literature and poetry, he was also remarkably kind and generous. His thought, his vision, his driving force, will continue to accompany us.

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Theoretical physicist Stanley Deser, a co-inventor of supergravity, passed away in Pasadena, California, on 21 April. 

Stanley was born to middle-class Jewish parents in Rovno, then in Poland. In 1935 the family emigrated first to Palestine and then to France. After the Second World War broke out they fled to the US via Portugal (they were one of the families saved by Aristides de Sousa Mendes), eventually settling in Brooklyn. Stanley graduated Summa Cum Laude from Brooklyn College in 1949, and received his PhD at Harvard in 1953 under the supervision of Julian Schwinger. After postdocs at the Institute for Advanced Study in Princeton, NJ (1953–1955) and the Niels Bohr Institute in Copenhagen (1955–1957), and a lectureship at Harvard University (1957–1958), he joined the faculty of the physics department at Brandeis in 1958, where he remained until he retired in 2005. After moving to Pasadena, he remained an emeritus professor at Brandeis, and continued to publish physics papers until this year (as well as his autobiography, Forks in the Road, in 2021).

Stanley was a towering figure in theoretical high-energy physics, classical gravity and quantum gravity. His work cuts through mathematical complexity with deep physical insight. His first signature work, the Arnowitt–Deser–Misner (ADM) formalism, gave a Hamiltonian initial-value formalism for general relativity. This work is the foundation of precise calculations in inflationary cosmology, needed to match cosmic microwave background observations; and in numerical relativity calculations needed to interpret the results of gravitational-wave experiments. He leaves behind a lifetime of work in theoretical physics that remains foundational, including co-inventing supergravity (contemporaneously with Ferrara, Freedman and van Nieuwenhuizen) and formulating the dynamics of the superstring with Zumino; showing that general theories with massive gravity are inconsistent; and developing topologically massive gauge theories and gravity with Jackiw and Templeton. 

Stanley was an important member of the scientific community. As Rainer Weiss, who shared the 2017 Nobel Prize in Physics for the observation of gravitational waves, related, he played an important role in convincing the National Science Foundation to fund the LIGO gravitational-wave detector. He was a fellow of the National Academy of Sciences (NAS) and the American Academy of Arts and Sciences; a foreign member of the Royal Society and the Torino Academy of Sciences; he was awarded the Dannie Heineman Prize in Mathematical Physics and the Einstein Medal, along with the Guggenheim and Fulbright awards; and held honorary doctorates from Stockholm University and the Chalmers Institute of Technology.

Stanley will be remembered for his wisdom and ready wit; emails and talks in which every sentence had multiple meanings and were packed with allusions and jokes; his delight and skill in acquiring languages; a love of travel; and a deep appreciation for art and literature.

Stanley was preceded in death by his wife, the artist Elsbeth Deser (daughter of Oskar Klein), and his daughter Eva. He leaves behind three daughters – retired linguist Toni Deser; thea­tre director Abigail Deser; and atmospheric scientist (and fellow NAS member) Clara Deser – and four grandchildren, Ursula, Oscar, Louise and Simon.

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Kitty presided over a close-knit team assembled from diverse backgrounds. She was a rather strict boss, in keeping with the usual unwritten standards of the time, but her team members still remember her fondly over 30 years later. Throughout her career at CERN, Kitty was unfailingly kind, cheerful and helpful towards all those who called on her services, from early-career researchers and technicians to Nobel prize-winners. Her mission was to help them disseminate their science in the best possible way, such as by working through the weekend with her team on the presentation of the discovery of the W boson.

Kitty was a much-loved institution of CERN. A lover of Italian opera, following her retirement from CERN she settled in Spain, where she lived for many years before passing away on 13 May, just four days before her 95th birthday. She is remembered fondly by many scientists who have passed through CERN over the decades.

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What got you into physics?

I have always been interested in what one might call existential questions: those that were originally theological or philosophical, but are now science, such as “why are things the way they are?” When I was young, for me it was a toss-up: do I go into particle physics or cosmology? At the time, experimental cosmology was less developed, so it made sense to go towards particle physics.

What has been your research focus?

When I was a graduate student in college, I was intrigued by the idea of quantum mechanical spin. I didn’t understand spin and I still don’t. It’s a perplexing and non-intuitive concept. It turned out the university I went to was working on it. When I got there, however, I ended up doing a fixed-target jet-photoproduction experiment. My thesis experiment was small, but it was a wonderful training ground because I was able to do everything. I built the experiment, wrote the data acquisition and all of the analysis software. Then I got back on track with the big questions, so colliders with the highest energies were the way to go. Back then it was the Tevatron and I joined DØ. When the LHC came online it was an opportunity to transition to CMS.

Why and when did you decide to get into communication?

It has to do with my family background. Many physicists come from families where one or both parents are already from the field. But I come from an academically impoverished, blue-collar background, so I had no direct mentors for physics. However, I was able to read popular books from the generation before me, by figures such as Carl Sagan, Isaac Asimov or George Gamow. They guided me into science. I’m essentially paying that back. I feel it’s sort of my duty because I have some skill at it and because I expect that there is some young person in some small town who is in a similar position as I was in, who doesn’t know that they want to be a scientist. And, frankly, I enjoy it. I am also worried about the antiscience sentiment I see in society, from the antivaccine movement to climate-change denial to 5G radiation fears. If scientists do not speak up, the antiscience voices are the only ones that will be heard. And if public policy is based on these false narratives, the damage to society can be severe. 

Scientists doing outreach create goodwill, which can lead to better funding for research-focused scientists

How did you start doing YouTube videos?

I had got to a point in my career where I was fairly established, and I could credibly think of other things. When you’re young, you are urged to focus entirely on research, because if you don’t, it could harm your research career. I had already been writing for Fermilab Today and I kept suggesting doing videos, as YouTube was becoming a thing. After a couple of years one of the videographers said, “You know, Don, you’re actually pretty good at explaining this stuff. We should do a video.” My first video came out a year before the Higgs discovery, in July 2011. It was on the Higgs boson. When the video came out, a few of the bigger science outlets picked it up and during the build-up to the Higgs excitement it got more and more views. By now it has more than three million clicks, which for a science channel is a lot. We do serious science in our videos, but there is also some light-heartedness in them.

Do you try to make the videos funny? 

This has more to do with me not taking anything seriously. I have found that irreverent humour can be disarming. People like to be entertained when they are learning. For example, one video was about “What was the real origin of mass?” Most people think that the Higgs boson is giving mass, but it’s really QCD. It’s the energy stored inside nucleons. In any event, in this video I start out with a joke about going into a Catholic church. The Higgs boson tries to say “I’m losing my faith,” and the priest replies: “You can’t leave the church. Without you how can we have mass?” For a lot of YouTube channels, viewership is not just about the material. It’s about the viewer liking the presenter. I’d say people who like our channel appreciate the combination of reliable science facts, but also subscribe for the humour. If a viewer doesn’t like a guy who does terrible dad jokes, they just go to another channel.

During the Covid-19 pandemic your videos switched to “Subatomic stories”. How do they differ?

Most of my videos are done in a studio on green screen so that we can put visuals in the background, but that was not possible during the lockdown. We then did a set up in my living room. I had an old DSLR camera and a recorder, and would record the video and the audio, then send the files to my videographer, Ian Krass, who does all the magic. Our usual videos don’t have a real story arc; they are just a series of topics. With “Subatomic stories” we began with a plan. I organised it as a sort of self-contained course, beginning with basic things, like the Standard Model, weak force, strong force, etc. Towards the end, we introduced more diverse, current research topics and a few esoteric theoretical ideas. Later, after Subatomic stories, I continued to film in my basement in a green-screen studio I built. We’ve returned to the Fermilab studio, but the basement one is waiting should the need arise. 

You are quite the public face of Fermilab. How does this relationship work?

It’s working wonderfully. I have no complaints. I can’t say that was always true in the past, because, when you’re young, you’re advised to focus on your research; it was like that for me. At the time there was some hostility towards science communicators. If you did outreach, you weren’t really considered a serious scientist, and that’s still true to a degree, although it is getting better. For me, it got to the point where people were just used to me doing it, and they tolerated it. As long as it didn’t bother my research, I could do this on my time. Some people bowl, some people knit, some people hike. I made videos. As I started becoming more successful, the laboratory started embracing the effort and even encouraged me to spend some of my work day on it. I was glad because in the same way that we encourage certain scientists to specialise in AI or computational skills or detector skills, I think that we as a field need to cultivate and encourage those scientists who are good at communicating our work. The bottom line is that I am very happy with the lab. I would like to see other laboratories encourage at least a small subset of scientists, those who are enthusiastic about outreach, to give them the time and the resources to do it, because there’s a huge payoff.

What are your favourite and least favourite things about doing outreach?

I think I’m making an impact. For instance, I’ve had graduate students or even postdocs ask me to autograph a book saying, “I went into physics because I read this book.” Occasionally I’m recognised in public, but the viewership numbers tell the story. If a video does poorly, it will get 50,000 viewers. And a good video, or maybe just a lucky one, can get millions. The message is getting out. As for the least favourite part, lately it is coming up with ideas. I’ve covered nearly every (hot) topic, so now I am thinking of revisiting early topics in a new way.

What would be your message to physicists who don’t have time or see the need for science communication?

Let’s start with the second type, who don’t see the value of it. I would like to remind them that essentially, in any country, if you want to do research, your funding comes from taxpayers. They work hard for their money and they certainly don’t want to pay taxes, so if you want to ask them to support this thing that you’re interested in, you need to convince them that it’s important and interesting. For those who don’t have time, I’m empathetic. Depending on your supervisor, doing science communication can harm a young career. However, in that case I think that the community should at least support a small group of people who do outreach. If nothing else, the scientists doing outreach create goodwill, which can lead to better funding for research-focused scientists.

Where do you see particle physics headed and the role of outreach?

The problem is that the Standard Model works well, but not perfectly. Consequently, we need to look for anomalies both at the LHC and with other precision experiments. I imagine that the next decade will resemble what we are doing now. I think it would be of very high value if we could spend some money on thinking about how to make stronger magnets and advanced acceleration technologies, because that’s the only way we’re going to get a very large increase in energy. The scientists know what to do. We are developing the techniques and technologies needed to move forward. On the communication side, we just need to remind the public that the questions particle physicists and cosmologists are trying to answer are timeless. They’re the questions many children ask. It’s a fascinating universe out there and a good science story can rekindle anyone’s sense of child-like wonder.

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The EPS High Energy and Particle Physics Prize is awarded for an outstanding contribution in a experimental, theoretical or technological achievement. This year, the recipients are Cecilia Jarlskog for the discovery of an invariant measure of CP violation in both quark and lepton sectors; and the Daya Bay and RENO collaborations for the observation of short-baseline reactor electron-antineutrino disappearance, providing the first determination of the neutrino mixing angle, which paves the way for the detection of CP violation in the lepton sector.

The 2023 Giuseppe and Vanna Cocconi Prize (honouring contributions in particle astrophysics and cosmology in the past 15 years) is awarded to the SDSS/BOSS/eBOSS collaborations for their outstanding contributions to observational cosmology, including the development of the baryon-acoustic oscillation measurement into a prime cosmological tool, using it to robustly probe the history of the expansion rate of the Universe back to one-fifth of its age providing crucial information on dark energy, the Hubble constant, and neutrino masses.

The 2023 Gribov Medal is awarded to Netta Engelhardt for her groundbreaking contributions to the understanding of quantum information in gravity and black-hole physics. This medal goes to early-career researchers working in theoretical physics or field theory.

The 2023 Young Experimental Physicist Prize of the High Energy and Particle Physics Division of the EPS ­– for early-career experimental physicists – is awarded to Valentina Cairo for her outstanding contributions to the ATLAS experiment: from the construction of the inner tracker, to the development of novel track and vertex reconstruction algorithms and to searches for di-Higgs boson production.

Honouring achievements in outreach, education, and the promotion of diversity, the 2023 Outreach Prize of the High Energy and Particle Physics Division of the EPS is awarded to Jácome (Jay) Armas. It recognizes his outstanding combination of activities on science communication, most notably for the “Science & Cocktails” event series, revolving around science lectures which incorporate elements of the nightlife such as music/art performances and cocktail craftsmanship and reaching out to hundreds of thousands in five different cities world-wide.

All awards will be presented at the EPS Conference on High Energy Physics, which will take place in Hamburg from 21 to 25 August.

Full citations can be found here: http://eps-hepp.web.cern.ch/eps-hepp/prizes.php

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Giorgio Brianti, a pillar of CERN throughout his 40-year career, passed away on 6 April at the age of 92. He played a major role in the success of CERN and in particular the LEP project, and his legacy lives on across the whole of the accelerator complex.

Giorgio began his engineering studies at the University of Parma and continued them for three years in Bologna, where he obtained his laurea degree in May 1954. Driven by a taste for research, he learned, thanks to his thesis advisor, that Edoardo Amaldi was setting up an international organization in Geneva called CERN and was invited to meet him in Rome in June 1954. In his autobiography – written for his family and friends – Giorgio describes this meeting as follows: “Edoardo Amaldi received me very warmly and, after various discussions, he said to me: ‘you can go home: you will receive a letter of appointment from Geneva soon’. I thus had the privilege of participating in one of the most important intellectual adventures in Europe, and perhaps the world, which in half a century has made CERN ‘the’ world laboratory for particle physics.”

Giorgio had boundless admiration for John Adams, who had been recruited by Amaldi a year earlier, recounting: “John was only 34 years old, but had a very natural authority. To say that we had a conversation would be an exaggeration, due to my still very hesitant English, but I understood that I was assigned to the magnet group”. After participating in the design of the main bending magnets for the Proton Synchrotron, Giorgio was sent by Adams to Genoa for three years to supervise the construction of 100 magnets made by the leading Italian company in the sector, Ansaldo. Upon his return, he was entrusted with the control group and in 1964 he was appointed head of the synchro-cyclotron (SC) division. After only four years he was asked to create a new division to build a very innovative synchrotron – the Booster – capable of injecting protons into the PS and significantly increasing the intensity of the accelerated current. He described this period as perhaps his happiest from a technical point of view. Adams – who had been appointed Director General of the new CERN-Lab II to construct the 400 GeV Super Proton Synchrotron (SPS) – also entrusted Giorgio with designing and building the experimental areas and their beam lines. The 40th anniversary of their inauguration was celebrated with him in 2018 and the current fixed-target experimental programme profits to this day from his foresight.

Giorgio has left us not only an intellectual but also a spiritual legacy

In January 1979 Giorgio was made head of the SPS division, but only two years later he was called to a more important role, that of technical director, by the newly appointed Director General Herwig Schopper. As Giorgio writes: “The main objectives of the mandate were to build the LEP… which was to be installed in a 27 km circumference tunnel over 100 m deep, and to complete the SPS proton-antiproton program, a very risky enterprise, but whose success in 1982 and 1983 was decisive for the future of CERN”. The enormous technical work required to transform the SPS into a proton-antiproton collider that went on to discover the W and Z bosons took place in parallel with the construction of LEP and the launch of the Large Hadron Collider (LHC) project, which Giorgio personally devoted himself to starting in 1982.

The LHC occupied Giorgio for nearly 15 years, starting from almost nothing. As he writes: “It was initially a quasi-clandestine activity to avoid possible reactions from the delegates of the Member States, who would not have understood an initiative parallel to that of the LEP. The first public appearance of the potential project, which already bore the name Large Hadron Collider, took place at a workshop held in Lausanne and at CERN in the spring of 1984.”

The LHC project received a significant boost from Carlo Rubbia, who became Director General in 1989 and appointed Giorgio as director of future accelerators. While LEP was operating at full capacity during these years, under his leadership new technologies were developed and the first prototypes of high-field superconducting magnets were created. The construction programme for the LHC was preliminarily approved in 1994, under the leadership of Chris Llewellyn Smith. In 1996, one year after Giorgio’s retirement, the final approval was granted. Giorgio continued to work, of course! In particular, in 1996 he agreed to chair the advisory committee of the Proton Ion Medical Machine Study, a working group established within CERN aimed at designing and developing a new synchrotron for medical purposes for the treatment of radio-resistant tumours with carbon ion beams. The first centre was built in Italy, in Pavia, by the Italian Foundation National Centre for Oncological Hadrontherapy (CNAO). He was also an active member of the editorial board of the book “Technology meets Research,” which celebrated 60 years of interaction at CERN between technology and fundamental science.

Giorgio has left us not only an intellectual but also a spiritual legacy. He was a man of great moral rigour, with a strong and contemplative Christian faith, determined to achieve his goals but mindful not to hurt others. He was very attached to his family and friends. His intelligence, kindness, and generosity shone through his eyes and – despite his reserved character – touched the lives of everyone he met.

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CMS collaborator Adinda de Wit (University of Zurich) was awarded the experimental prize for her achievements in understanding the nature of the Higgs boson, including precision studies of its couplings and decay channels. She received her PhD from Imperial College London, then took up a postdoc position at DESY followed by the University of Zurich and is presently at LLR. Co-convener of the CMS Higgs physics analysis group and past co-convener of the CMS Higgs combination and properties group, de Wit also received the Herta-Sponer-Prize by the German Physical Society.

Yong Zhao (Argonne National Laboratory) was awarded the theory prize for fundamental contributions to ab initio calculations of parton distributions in lattice QCD. He received his PhD from the University of Maryland, and then held postdoc positions at Brookhaven and  MIT before joining Argonne laboratory as an assistant physicist. Yong also received the 2022 Kenneth G. Wilson Award for Excellence in Lattice Field Theory for fundamental contributions to calculations of parton physics on lattice.

During the award ceremony, Nobel laureate Giorgio Parisi joined in via Zoom to reminisce about his collaboration with Altarelli. Together they contributed to QCD evolution equations for parton densities, known as the Altarelli-Parisi or DGLAP equations.

The DIS series covers a large spectrum of topics in high-energy physics. One part of the conference is devoted to the most recent results from large experiments at Brookhaven, CERN, DESY, Fermilab, Jlab and KEK, as well as corresponding theoretical advances. The workshop demonstrated how DIS and related subjects permeate a broad range of physics topics from hadron colliders to spin physics, neutrino physics and more. The next workshop will be held in Grenoble, France from 8-12 April 2024.

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Visiting CERN was an invaluable experience that led to lifelong connections. “Meeting people who worked on particle-physics missions always piqued my interest, as they had such interesting stories and experiences to share,” Valeria explains. “I collaborated and worked alongside people from different areas in cosmology and particle physics, and I got the opportunity to connect with scientists working in different experiments.”

After the fellowship, Valeria went to the University of Heidelberg as a research group leader, and during this time she was selected for the “Science to Data Science” programme by the AI software company Pivigo. Working on artificial intelligence and unsupervised learning to analyse healthcare data for a start-up company in London, it presented her with the opportunity to widen her skillset. 

Valeria’s career trajectory turned towards space science in 2007, when she began working for the Euclid mission of the European Space Agency (ESA) due to launch this year, with the aim to measure the geometry of the universe for the study of dark matter and energy. Currently co-lead of the Euclid theory science working group, Valeria has held a number of roles in the mission, including deputy manager of the communication group. In 2018 she became the CEA representative for Euclid–France communication and is currently director of research for the CEA astrophysics department/CosmoStat lab. She also worked on data analysis for ESA’s Planck mission from 2009 to 2018. 

Mentoring and networking 

In both research collaborations, Valeria worked on numerous projects that she coordinated from start to finish. While leading teams, she studied management with the goal of enabling everyone to reach their full potential. She also completed training in science diplomacy, which helped her gain valuable transferrable skills. “I decided to be proactive in developing my knowledge and started attending webinars, and then training on science diplomacy. I wanted to deepen my understanding on how science can have an impact on the world and society.” In 2022 Valeria was selected to participate in the first Science Diplomacy Immersion Programme organised by the Geneva Science and Diplomacy Anticipator (GESDA), which aims to take advantage of the ecosystem of international organisations in Geneva to anticipate, accelerate and translate emerging scientific themes into concrete actions. 

I wanted to deepen my understanding on how science can have an impact on the world and society

Sharing experience and building connections between people have been a theme in Valeria’s career. Nowhere is this better illustrated than her role, since 2015, as a mentor for the Supernova Foundation – a worldwide mentoring and networking programme for women in physics. “Networking is very important in any career path and having the opportunity to encounter people from a diverse range of backgrounds allows you to grow your network both personally and professionally. The mentoring programme is open to all career levels. There are no barriers. It is a global network of people from 53 countries and there are approximately 300 women in the programme. I am convinced that it is a growing community that will continue to thrive.” Valeria has also acted as mentor for Femmes & Science (a French initiative by Paris-Saclay University) in 2021–2022, and was recently appointed as one of 100 mentors worldwide for #space4women, an initiative of the United Nations Office of Outer Space Affairs to support women pursuing studies in space science.

A member of the CERN Alumni Network, Valeria thoroughly enjoys staying connected with CERN. “Not only is the CERN Alumni Network excellent for CERN as it brings together a wide range of people from many career paths, but it also provides an opportunity for its members to understand and learn how science can be used outside of academia.”

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Sigurd was born on 15 February 1944 in Böhmisch-Kamnitz (Bohemia) and studied physics at TH Darmstadt, where he received his diploma in 1969 and his doctorate in 1974 with Egbert Kankeleit. Afterwards, he joined the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, his scientific work there occupying him for almost 50 years. Accuracy and scientific exactness were important to him from the beginning. He investigated fusion reactions and radioactive decays in the group of Peter Armbruster and worked with Gottfried Münzenberg. 

Sigurd achieved international fame through the discovery of proton radioactivity from the ground state of ¹⁵¹Lu in 1981, a previously unknown decay mechanism. When analysing the data, he benefited from his pronounced thoroughness and scientific curiosity. At the same time, he begun work on the synthesis, unambiguous identification and study of the properties of the heaviest chemical elements, which were to shape his further scientific life. The first highlights were the synthesis of the new elements bohrium (Bh), hassium (Hs) and meitnerium (Mt) between 1981 and 1984, with which GSI entered the international stage of this renowned research field. The semiconductor detectors that Sigurd had developed specifically for these experiments were far ahead of their time, and are now used worldwide to search for new chemical elements. 

At the end of the 1990s Sigurd took over the management of the Separator for Heavy Ion Reaction Products (SHIP) group and, after making instrumental improvements to detectors and electronics, crowned his scientific success with the discovery of the elements darmstadtium (Ds), roentgenium (Rg) and copernicium (Cn) in the years 1994 to 1996. The concept for “SHIP-2000”, a strategy paper developed under his leadership in 1999 for long-term heavy-element research at GSI, is still relevant today. In 2009 he was appointed Helmholtz professor and from then on was able to devote himself entirely to scientific work again. For many years he also maintained an intensive collaboration and scientific exchange with his Russian colleagues in Dubna, where he co-discovered the element flerovium (Fl) in a joint experiment.

For his outstanding research work and findings, Sigurd received a large number of renowned awards and prizes; too many, in fact, to mention. A diligent writer and speaker, he was invited to talk at countless international conferences, authored a large number of review articles, books and book chapters, and many widely cited publications. He also liked to present scientific results at public events. In doing so, he was able to develop a thrilling picture of modern physics, but also of the big questions of cosmology and element synthesis in stars; he was also able to convey very clearly to the public how atoms can be made “visible”.

Many chapters of Sigurd’s contemporary scientific life are recorded in his 2002 book On Beyond Uranium (CRC Press). His modesty and friendly nature were remarkable. You could always rely on him. His care, accuracy and deliberateness in all work were outstanding, and his persistence was one of the foundations for ground-breaking scientific achievements. He was always in the office or at an experiment, even late in the evening and on weekends, so you could talk to him at any time and were always rewarded with detailed answers and competent advice.

We are pleased that we were able to work with such an excellent scientist and colleague, as well as an outstanding teacher and a great person, for so many years.

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After finishing his studies in physics at the University of Leuven (Belgium), Karel joined CERN in 1983 as engineer-in-charge of the Super Proton Synchrotron (SPS) at the time when the machine was operated as a proton–antiproton collider. During his career Karel greatly contributed to the commissioning and performance development and follow-up of the SPS during its various phases as proton–antiproton collider, LEP injector, high-intensity fixed-target machine and as the LHC injector of proton and ion beams. He had a profound and extensive knowledge of the machine, from complex beam dynamics aspects to the engineering details of its various systems, and was the reference whenever new beam requirements or modes of operation were discussed. 

Karel was an extremely competent and rigorous physicist, but also a generous and dedicated mentor who trained generations of control-room technicians, shift leaders and machine physicists and engineers, helping them to grow and take on responsibilities while remaining available to lend a hand when needed. His positive attitude and humour have left a lasting imprint, so much so that “Think like a proton: always positive!” has become the motto of the SPS operation team, and is now visible in the SPS island in the CERN Control Centre.

Karel had the rare gift of explaining complex phenomena with simple but accurate models and clear examples, whether it was accelerator physics and technology, or physics and engineering more generally. He gave a fascinating series of machine shut-down lectures covering the history of the SPS, synchrotron radiation and one of his passions, aviation, with a talk on “Air and the airplanes that fly in it”. 

Karel was a larger-than-life tutor, friend, reference point, expert and father figure to generations of us. He was much missed in the SPS island and beyond following his retirement in September 2019, and will be even more so now.  

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Born in Czerteż, Poland, Jadach graduated in 1970 with a masters in physics from Jagiellonian University. There, he also defended his doctorate, received his habilitation degree and worked until 1992. During this period, whilst partly under martial law in Poland, Jadach took trips to Leiden, Paris, London, Stanford and Knoxville, and formed collaborations on precision theory calculations based on Monte Carlo event-generator methods. In 1992 he moved to the Institute of Nuclear Physics Polish Academy of Sciences (PAS) where, receiving the title of professor in 1994, he worked until his death. 

Prior to LEP, all calculations of radiative corrections were based on first- and, later, partially second-order results. This limited the theoretical precision to the 1% level, which was unacceptable for experiment. In 1987 Jadach solved that problem in a single-author report, inspired by the classic work of Yennie, Frautschi and Suura, featuring a new calculational method for any number of photons. It was widely believed that soft-photon approximations were restricted to many photons with very low energies and that it was impossible to relate, consistently, the distributions of one or two energetic photons to those of any number of soft photons. Jadach and his colleagues solved this problem in their papers in 1989 for differential cross sections, and later in 1999 at the level of spin amplitudes. A long series of publications and computer programmes for re-summed perturbative Standard Model calculations ensued. 

Most of the analysis of LEP data was based exclusively on the novel calculations provided by Jadach and his colleagues. The most important concerned the LEP luminosity measurement via Bhabha scattering, the production of lepton and quark pairs, and the production and decay of W and Z boson pairs. For the W-pair results at LEP2, Jadach and co-workers intelligently combined separate first-order calculations for the production and decay processes to achieve the necessary 0.5% theoretical accuracy, bypassing the need for full first-order calculations for the four-fermion process, which were unfeasible at the time. Contrary to what was deemed possible, Jadach and his colleagues achieved calculations that simultaneously take into account QED radiative corrections and the complete spin–spin correlation effects in the production and decay of two tau leptons. He also had success in the 1970s in novel simulations of strong interaction processes.

After LEP, Jadach turned to LHC physics. Among other novel results, he and his collaborators developed a new constrained Markovian algorithm for parton cascades, with no need to use backward evolution and predefined parton distributions, and proposed a new method, using a “physical” factorisation scheme, for combining a hard process at next-to leading order with a parton cascade, much simpler and more efficient than alternative methods.

Jadach was already updating his LEP-era calculations and software towards the increased precision of FCC-ee, and is the co-editor and co-author of a major paper delineating the need for new theoretical calculations to meet the proposed collider’s physics needs. He co-organised and participated in many physics workshops at CERN and in the preparation of comprehensive reports, starting with the famous 1989 LEP Yellow Reports.

Jadach, a member of the Polish Academy of Arts and Sciences (PAAS), received the most prestigious awards in physics in Poland: the Marie Skłodowska-Curie Prize (PAS), the Marian Mięsowicz Prize (PAAS), and the prize of the Minister of Science and Higher Education for lifetime scientific achievements. He was also a co-initiator and permanent member of the international advisory board of the RADCOR conference.

Stanisław (Staszek) was a wonderful man and mentor. Modest, gentle and sensitive, he did not judge or impose. He never refused requests and always had time for others. His professional knowledge was impressive. He knew almost everything about QED, and there were few other topics in which he was not at least knowledgeable. His erudition beyond physics was equally extensive. He is already profoundly and dearly missed.

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Vittorio graduated in 1965 from the University of Naples Federico II. He soon moved to CERN as a fellow, where he remained from 1966 to 1969, contributing to the design and commissioning of the first high-intensity hadron collider, the Intersecting Storage Rings. At CERN, Vittorio introduced the concept of beam-coupling impedance to model the instabilities that were experienced above transition energy, writing a seminal report (Longitudinal instability of a coasting beam above transition, due to the action of lumped discontinuities), in which he described for the first time the action of discontinuities in the transverse section of a beam pipe as an impedance. His theory, which after his initial intuition he developed together with Andy Sessler, Alessandro G Ruggiero and many other colleagues, has become a fundamental tool in the design of particle accelerators. 

In 1969 he returned to his alma mater in Naples as professor of electromagnetic fields at the faculty of engineering, and continued teaching until he retired. He created an accelerator-physics team in association with INFN within the faculty of physics, and throughout his career remained closely related to CERN, where he visited regularly and where he sent many of his students. 

Vittorio collaborated with practically all the studies and accelerator projects in Europe, from the CERN machines to DAFNE, the European Spallation Source and HERA-B at DESY. The group in Naples became, thanks to him, a reference in the world of accelerators for the development of the theory of beam-coupling impedance of accelerator components and the associated bench measurements. Since the mid-1990s, he became increasingly interested in the development of linear accelerators for proton therapy, participating in a large collaboration with the TERA foundation, CERN and INFN. In 2003 he led a new collaboration between the University of Naples and several sections of INFN, which produced the first linac module at 3 GHz capable of accelerating protons from a 30 MeV cyclotron.

In 2019 Vittorio was awarded the IPAC Xie Jialin Award for outstanding work in the accelerator field “For his pioneering studies on instabilities in particle-beam physics, the introduction of the impedance concept in storage rings and, in the course of his academic career, for disseminating knowledge in accelerator physics throughout many generations of young scientists”.

It is difficult to find the words to recall Vittorio’s immense human qualities, his deep culture and his profound humanity. Several of his students are now scattered around the world, continuing his efforts to propose technical solutions to accelerator-physics problems based on a deep understanding of the phenomena of beam instability. Vittorio was moved by a sincere passion for science, and an irresistible curiosity for everything and everyone around him, which always brought him to approach anyone with an open and friendly spirit. 

We will deeply miss a passionate mentor and colleague, his wide knowledge, energy, friendship and humanity. 

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I take a view that a lot of my colleagues will not be too happy with. String theory is a very precise mathematical structure, so precise that many mathematicians have won Fields medals by making contributions that were string-theory motivated. It’s supersymmetric. It exists in flat or anti-de Sitter space (that is, a space–time with a negative curvature in the absence of matter or energy). And although we may not understand it fully at present, there does appear to be an exact mathematical structure there. I call that string theory with a capital “S”, and I can tell you with 100% confidence that we don’t live in that world. And then there’s string theory with a small “s” – you might call it string-inspired theory, or think of it as expanding the boundaries of this very precise theory in ways that we don’t know how to at present. We don’t know with any precision how to expand the boundaries into non-supersymmetric string theory or de Sitter space, for example, so we make guesses. The string landscape is one such guess. It’s not based on absolutely precise capital-S string theory, but on some conjectures about what this expanded small-s string theory might be. I guess my prejudice is that some expanded version of string theory is probably the right theory to describe particle physics. But it’s an expanded version, it’s not supersymmetric. Everything we do in anti-de-Sitter-space string theory is based on the assumption of absolute perfect supersymmetry. Without that, the models we investigate are rather speculative. 

How has the lack of supersymmetric discoveries at the LHC impacted your thinking?

All of the string theories we know about with any precision are exactly supersymmetric. So if supersymmetry is broken at the weak scale or beyond, it doesn’t help because we’re still facing a world that is not exactly supersymmetric. This only gets worse as we find out that supersymmetry doesn’t seem to even govern the world at the weak scale. It doesn’t even seem to govern it at the TeV scale. But that, I think, is secondary. The first primary fact is that the world is not exactly supersymmetric and string theory with a capital S is. So where are we? Who knows! But it’s exciting to be in a situation where there is confusion. Anything that can be said about how string theory can be precisely expanded beyond the supersymmetric bounds would be very interesting. 

What led you to coin the string theory “landscape” in 2003? 

A variety of things, among them the work of other people, in particular Polchinski and Bousso, who conjectured that string theories have a huge number of solutions and possible behaviours. This was a consequence, later articulated in a 2003 paper abbreviated “KKLT” after its authors, of the innumerable (initial estimates put it at more than 10⁵⁰⁰) different ways the additional dimensions of string theory can be hidden or “compactified”. Each solution has different properties, coupling constants, particle spectra and so forth. And they describe different kinds of universes. This was something of a shock and a surprise; not that string theory has many solutions, but that the numbers of these possibilities could be so enormous, and that among those possibilities were worlds with parameters, in particular the cosmological constant, which formed a discretuum as opposed to a continuum. From one point of view that’s troubling because some of us, me less than others, had hoped there was some kind of uniqueness to the solutions of string theory. Maybe there was a small number of solutions and among them we would find the world that we live in, but instead we found this huge number of possibilities in which almost anything could be found. On the other hand, we knew that the parameters of our world are unusual, exceptional, fine-tuned – not generic, but very special. And if the string landscape could say that there would be solutions containing the peculiar numbers that we face in physics, that was interesting. Another motivation came from cosmology: we knew on the basis of cosmic-microwave-background experiments and other things that the portion of the universe we see is very flat, implying that it is only a small part of the total. Together with the peculiar fine-tunings of the numbers in physics, it all fitted a pattern: the spectrum of possibilities would not only be large, but the spectrum of things we could find in the much bigger universe that would be implied by inflation and the flatness of the universe might just include all of these various possibilities. 

So that’s how anthropic reasoning entered the picture?

All this fits together well with the anthropic principle – the idea that the patterns of coupling constants and particle spectra were conditioned on our own existence. Weinberg was very influential in putting forward the idea that the anthropic principle might explain a lot of things. But at that time, and probably still now, many people hated the idea. It’s a speculation or conjecture that the world works this way. The one thing I learned over the course of my career is not to underestimate the potential for surprises. Surprises will happen, patterns that look like they fit together so nicely turn out to be just an illusion. This could happen here, but at the moment I would say the best explanation for the patterns we see in cosmology and particle physics is a very diverse landscape of possibilities and an extremely large universe – a multiverse, if you like – that somehow manifests all of these possibilities in different places. Is it possible that it’s wrong? Oh yes! We might just discover that this very logical, compelling set of arguments is not technically right and we have to go in some other direction. Witten, who had negative thoughts about the anthropic idea, eventually gave up and accepted that it seems to be the best possibility. And I think that’s probably true for a lot of other people. But it can’t have the ultimate influence that a real theory with quantitative predictions can have. At present it’s a set of ideas that fit together and are somewhat compelling, but unfortunately nobody really knows how to use this in a technical way to be able to precisely confirm it. That hasn’t changed in 20 years. In the meantime, theoretical physicists have gone off in the important direction of quantum gravity and holography. 

What do you mean by holography in the string-theory context?

Holography predates the idea of the landscape. It was based on Bekenstein’s observation that the entropy of a black hole is proportional to the area of the horizon and not the volume of the black hole. It conjectures that the 3D world of ordinary experience is an image of reality coded on a distant 2D surface. A few years after the holographic principle was first conjectured, two precise versions of it were discovered; so called M(atrix) theory in 1996 and Maldacena’s “AdS/CFT” correspondence in 1997. The latter has been especially informative. It holds that there is a holographic duality between anti-de Sitter space formulated in terms of string theory, and quantum field theories that are similar to those that describe elementary particles. I don’t think string theory and holography are inconsistent with each other. String theory is a quantum theory that contains gravity, and all quantum mechanical gravity theories have to be holographic. String theory and holographic theory could well be the same thing. 

Almost anything we learn will be a large fraction of what we know

One of the things that troubles me about the standard model of cosmology, with inflation and a positive cosmological constant, is that the world, or at least the portion of it that we see, is de Sitter space. We do not have a good quantum understanding of de Sitter space. If we ultimately learn that de Sitter space is impossible, that would be very interesting. We are in a situation now that is similar to 20 years ago, where very little progress has been made in the quantum foundations of cosmology and in particular in the so-called measurement problem, where we don’t know how to use these ideas quantitatively to make predictions. 

What does the measurement problem have to do with it? 

The usual methodology of physics, in particular quantum mechanics, is to imagine systems that are outside the systems we are studying. We call these systems observers, apparatuses or measuring devices, and we sort of divide the world into those measuring devices and the things we’re interested in. But it’s quite clear that in the world of cosmology/de Sitter space/eternal inflation, that we’re all part of the same thing. And I think that’s partly why we are having trouble understanding the quantum mechanics of these things. In AdS/CFT, it’s perfectly logical to think about observers outside the system or observers on the boundary. But in de Sitter space there is no boundary; there’s only everything that’s inside the de Sitter space. And we don’t really understand the foundations or the methodology of how to think about a quantum world from the inside. What we’re really lacking is the kind of precise examples we have in the context of anti-de Sitter space, which we can analyse. This is something I’ve been looking for, as have many others including Witten, without much success. So that’s the downside: we don’t know very much.

What about the upsides? 

The upside is that almost anything we learn will be a large fraction of what we know. So there’s potential for great developments by simply understanding a few things about the quantum mechanics of de Sitter space. When I talk about this to some of my young friends, they say that de Sitter space is too hard. They are afraid of it. People have been burned over the years by trying to understand inflation, eternal inflation, de Sitter space, etc, so it’s much safer to work on anti-de Sitter space. My answer to that is: yes, you’re right, but it’s also true that a huge amount is known about anti-de Sitter space and it’s hard to find new things that haven’t been said before, whereas in de Sitter space the opposite is true. We will see, or at least the young people will see. I am getting to the point where it is hard to absorb new ideas.

To what extent can the “swampland” programme constrain the landscape?

The swampland is a good idea. It’s the idea that you can write down all sorts of naive semi-classical theories with practically infinite options, but that the consistency with quantum mechanics constrains the things that are possible, and those that violate the constraints are called the swampland. For example, the idea that there can’t be exact global symmetries in a quantum theory of gravity, so any theory you write down that has gravity and has a global symmetry in it, without having a corresponding gauge symmetry, will be in the swampland. The weak-gravity conjecture, which enables you to say something about the relative strengths of gauge forces and gravity acting on certain particles, is another good idea. It’s good to try to separate those things you can write down from a semi-classical point of view and those that are constrained by whatever the principles of quantum gravity are. The detailed example of the cosmological constant I am much less impressed by. The argument seems to be: let’s put a constraint on parameters in cosmology so that we can put de Sitter space in the swampland. But the world looks very much like de Sitter space, so I don’t understand the argument and I suspect people are wrong here.

What have been the most important and/or surprising physics results in your career?

I had one big negative surprise, as did much of the community. This was a while ago when the idea of “technicolour” – a dynamical way to break electroweak symmetry via new gauge interactions – turned out to be wrong. Everybody I knew was absolutely convinced that technicolour was right, and it wasn’t. I was surprised and shocked. As for positive surprises, I think it’s the whole collection of ideas called “it from qubit”. This has shown us that quantum mechanics and gravity are much more closely entangled with each other than we ever thought, and that the apparent difficulty in unifying them was because they were already unified; so to separate and then try to put them back together using the quantisation technique was wrong. Quantum mechanics and gravity are so closely related that in some sense they’re almost the same thing. I think that’s the message from the past 20 – and in particular the past 10 – years of it–from-qubit physics, which has largely been dominated by people like Maldacena and a whole group of younger physicists. This intimate connection between entanglement and spatial structure – the whole holographic and “ER equals EPR” ideas – is very bold. It has given people the ability to understand Hawking radiation, among other things, which I find extremely exciting. But as I said, and this is not always stated, in order to have real confidence in the results, it all ultimately rests on the assumption of theories that have exact supersymmetry. 

What are the near-term prospects to empirically test these ideas?

One extremely interesting idea is “quantum gravity in the lab” – the idea that it is possible to construct systems, for example a large sphere of material engineered to support surface excitations that look like conformal field theory, and then to see if that system describes a bulk world with gravity. There are already signs that this is true. For example, the recent claim, involving Google, that two entangled quantum computers have been used to send information through the analogue of a wormhole shows how the methods of gravity can influence the way quantum communication is viewed. It’s a sign that quantum mechanics and gravity
are not so different.

Do you have a view about which collider should follow the LHC? 

You know, I haven’t done real particle physics for a long time. Colliders fall into two categories: high-precision e⁺e^– colliders and high-energy proton–proton ones. So the question is: do we need a precision Higgs factory at the TeV scale or do we want to search for new phenomena at higher energies? My prejudice is the latter. I’ve always been a “slam ‘em together and see what comes out” sort of physicist. Analysing high-precision data is always more clouded. But I sure wouldn’t like anyone to take my advice on this too seriously.

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Experimental particle physicist Meenakshi Narain, an inspirational leader and champion of diversity, died unexpectedly on 1 January 2023 in Providence, RI. Considered by many as a “force of nature”, Meenakshi’s impact on the physics community has left an indelible mark.

Meenakshi grew up in Gorakhpur, India and emigrated to the US in 1984 for graduate school at SUNY Stony Brook. Her PhD thesis, based on data taken by the CUSB-II detector at CESR, utilised inclusive photon spectra from upsilon decays for both spectroscopy measurements and searches for exotic particles, including the Higgs boson. In 1991 Meenakshi joined Fermilab as a postdoc on the DØ experiment, where she was a principal player in the 1995 discovery of the top quark, leading a group searching for top anti–top pair production in the dilepton channel. Over the next decade, as a Fermilab Wilson Fellow and a faculty member at Boston University, she made seminal contributions to measurements of top-quark pair and single-top production, as well as to the top-quark mass, width and couplings. 

In 2007, upon joining the faculty at Brown University, Meenakshi joined the CMS experiment at the LHC. In addition to pioneering a number of exotic searches for high-mass resonances, new heavy gauge bosons and top-quark partners, she continued to make innovative contributions to precision top-quark measurements. Her foundational work on b- and c-quark identification also paved the way for Higgs boson searches and measurements. As a leader of the CMS upgrade studies group, Meenakshi coordinated physics studies for several CMS technical design reports for the High-Luminosity LHC upgrade, and an impressive number of results for the CERN yellow reports. She was also a key contributor to the US CMS outer tracker upgrade. 

The tutorials and workshops Meenakshi organised as co-coordinator of the LHC Physics Center (LPC) were pivotal in advancing the careers of many young scientists, whom she cared about deeply. As chair of the US CMS collaboration board, she was a passionate advocate for the LHC research programme. She created an inclusive, supportive community that participated in movements such as Black Lives Matter, and tackled numerous challenges imposed by the COVID-19 pandemic.

A strong voice for women and under-represented minorities in physics, Meenakshi was the founding co-chair of the CMS diversity office and the driving force behind the CMS task force on diversity and inclusion and the CMS women’s forum. She mentored a large group of students, post-docs and scientists from diverse backgrounds, and created PURSUE – an internship programme that provides summer research opportunities at CMS to students from minority-serving institutions.

Meenakshi’s illustrious career has been recognised via numerous accolades and positions of responsibility. She is remembered for her recent co-leadership of the Snowmass energy-frontier study, her service on HEPAP and her new appointment to the P5 subpanel, in addition to her new position as the first woman to chair the physics department at Brown. She will be remembered as a brilliant scientist, a beloved mentor and an inspiring leader who made the world a better, more equitable and inclusive place.

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It is with great sadness that we learnt of the passing of Lars Brink on 29 October 2022 at the age of 78. Lars Brink was an emeritus professor at Chalmers University Göteborg, Sweden and a member of the Royal Swedish Academy. He started his career as a fellow in the CERN theory group (1971–1973), which was followed by a stay at Caltech as a scientific associate (1976–1977). In subsequent years he was a frequent visitor at CERN, Caltech and ITP Santa Barbara, before becoming a full professor of theoretical physics at Chalmers in 1986, which under his guidance became an internationally leading centre for string theory and supersymmetric field theories. 

Lars held numerous other appointments, in particular as a member and chairperson on the board of NORDITA, the International Center for Fundamental Physics in Moscow, and later as the chairperson of the advisory board of the Solvay Foundation in Brussels. Since 2004 he was an external scientific member of the Max Planck Institute for Gravitational Physics in Golm. During his numerous travels Lars was welcomed by many leading institutions all over the world. He also engaged in many types of community service, such as the coordination of the European Union network “Superstring Theory” since 2000. Most importantly, he served on the Nobel Committee for physics many years, and as its chairperson for the 2013 Nobel Prize in Physics awarded to François Englert and Peter Higgs. 

Lars was a world-class theoretical physicist, with many pioneering contributions, especially to the development of supergravity and superstring theory, as well as many other topics. One of his earliest contributions was a beautiful derivation of the critical dimension of the bosonic string (with Holger Bech Nielsen), obtained by evaluating the formally divergent sum over zero-point energies of the infinitely many string oscillators; this derivation is now considered a standard textbook result. In 1976, with Paolo Di Vecchia and Paul Howe, he presented the first construction of the locally supersymmetric world-sheet Lagrangian for superstrings (also derived by Stanley Deser and Bruno Zumino) which now serves as the basis for the quantisation of the superstring and higher loop calculations in the Polyakov approach. His seminal 1977 work with Joel Scherk and John Schwarz on the construction of maximal (N = 4) supersymmetric Yang–Mills theory in four dimensions laid the very foundation for key developments of modern string theory and the AdS/CFT correspondence that came to dominate string-theory research only much later. Independently of Stanley Mandelstam, he proved the UV finiteness of the N = 4 theory in the light-cone gauge in 1983, together with Olof Lindgren and Bengt Nilsson – another groundbreaking result. Equally influential is his work with Michael Green and John Schwarz on deriving supergravity theories as limits of string amplitudes. More recently, he devoted much effort to a reformulation of N = 8 supergravity in light-cone super-space (with Sudarshan Ananth and Pierre Ramond). His last project before his death was a reevaluation and pedagogical presentation of Yoichiro Nambu’s seminal early papers (with Ramond).

Lars received numerous honours during his long career. In spite of these achievements he remained a kind, modest and most approachable person. Among our many fondly remembered encounters we especially recall his visit to Potsdam in August 2013, when he revived an old tradition by inviting the Nobel Committee to a special retreat for its final deliberations. The concluding discussions of the committee thus took place in Einstein’s summer house in Caputh. Of course, we were all curious for any hints from the predictably tight-lipped Swedes in advance of the official Nobel announcement, but in the end the only useful information we got out of Lars was that the committee had crossed the street for lunch to eat mushroom soup in a local restaurant!

He leaves behind his wife Åsa, and their daughters Jenny and Maria with their families, to whom we express our sincere condolences. We will remember Lars Brink as a paragon of scientific humility and honesty, and we miss a great friend and human being.

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While the motivations for leaving academia expressed by the speakers differed according to their personal stories, common themes emerged. The long time-scales of experimental physics coupled with job instability and the glacial pace of funding cycles for new projects, for example, sometimes led to demotivation, whereas the speakers found that industry had exciting shorter-term projects to explore. Several speakers sought a better work–life balance in subjects they could enthuse about, having previously experienced a sense of stagnation. Another factor related to that balance was the better ratio between salary and performance, and hours worked.

Case studies 

Caterina Deplano, formerly an ALICE experimentalist, and Giorgia Rauco, ex-CMS, described the personal constraints that led them to search for a job in the local area, and showed that this need not be a limiting factor. Both assessed their skills frankly and opted for further training in their target sectors: education and data science, respectively. Deplano’s path to teaching in Geneva led her to go back and study for four years, improving her French-language skills while obtaining a Swiss teaching qualification. The reward was apparent in the enthusiasm with which she talked about her students and her chosen career. Rauco explained how she came to contemplate life outside academia and talked participants through the application process, emphasising that finding the “right” employment fit had meant many months of work with frequent disappointments, the memory of which was erased by the final acceptance letter. Both speakers gave links to valuable resources for training and further education, and Rauco offered some top-tips for prospective transitioners: be excited for what is coming next, start as soon as possible if you are thinking about changing and don’t feel guilty about your choice.

Maria Elena Stramaglia, formerly ATLAS, described the anguish of deciding whether to stay in academia or go to industry, and her frank assessment of transferable skills weighed up against personal desires and her own work–life balance. Her decision to join Hitachi Energy was based on the right mix of personal and technical motivation, she said. In moving from LHCb to data science and management, Albert Puig Navarro joined a newly established department at Proton (the developers of ProtonMail, which was founded by former ATLAS members; CERN Courier September/October 2019 p53), in which he ended up being responsible for hiring a mix of data scientists, engineers and operations managers, conducting more than 200 interviews in the process. He discussed the pitfalls of over-confidence, the rather different requirements of the industrial sector, and the shift in motivations between pure science and industry. Cécile Deterre, a former ATLAS physicist now working on technology for sustainable fish farming, focussed on CV-writing for industrial job applications, during which she emphasised transferable skills and how to make your technical experience more accessible to future employers.

With one foot still firmly in particle physics, Alex Winkler, formerly CMS, joined a company that makes X-ray detectors for medical, security and industrial applications; in a serendipitous exception among the speakers, he described how he was head-hunted while contemplating life beyond CERN, and mentioned the novel pressures implicit in working in a for-profit environment. Massimo Marino, ex-ATLAS, gave a lively talk about his experiences in a number of diverse environments: Apple, the World Economic Forum and the medical energy industries, to name a few. Diverting along the way to write a series of books, his talk covered the personal challenges and expectations in different roles and environments over a long career.

Throughout the evening, which culminated in a panel session, participants had the opportunity to quiz the speakers about their sectors and the personal decisions and processes that led them there. Head of CERN Alumni Relations Rachel Bray also explained how the Alumni Network can help facilitate contact between current CERN members and their predecessors who have left the field. The interest shown by the audience and the detailed testimonials of the speakers demonstrated that this event remains a vital source of information and encouragement for those considering a career transition.

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Gabriella Pálla, who laid the foundations for the participation of Hungarian groups in CERN experiments, passed away on 11 October 2022 at the age of 88.

Gabriella attended Eötvös Loránd University in 1953, and began her career in nuclear physics in 1958 at the KFKI Research Institute for Particle and Nuclear Physics. Her first position was at the atomic physics department under the supervision of Károly Simonyi (on the topic of fast neutron reactions). In the 1970s she received a Humboldt Research Fellowship and worked at the cyclotron at the University of Hamburg, later at Jülich. She received her PhD in 1972 at Eötvös University and gained a DSc titled “Direct reactions and the collective properties of nuclei” in 1987.

In the 1990s Gabriella’s attention turned towards heavy-ion physics. She helped initiate the Buda-TOF project at NA49 and NA61 and later became the Hungarian ALICE representative in the early years of the experiment. She received the Academy Prize in Physics from the Hungarian Academy of Sciences in 1999 and the Simonyi Károly Award in 2010.

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When did you first know you had a passion for pure mathematics? 

I have had a passion for mathematics since my first year in school. At that time I did not realise what “pure mathematics” was, but maths was my favourite subject from a very early age.

What is number theory, in terms that a humble particle physicist can understand?

In fact, “number theory” is not well defined and any interesting question about numbers, geometric shapes and functions can be seen as a question for a number theorist.

What motivated you to work on sphere-packing? 

I think it is a beautiful problem, something that can be easily explained. Physicists know what a Euclidean space and a sphere are, and everybody knows the problem from stacking oranges or apples. What is a bit harder to explain is that mathematicians are not trying to model a particular physical situation. Mathematicians are not bound to phenomena in nature to justify their work, they just do it. We do not need to model any physical situation, which is a luxury. The work could have an accidental application, but this is not the primary goal. Physicists, especially theorists, are used to working in multi-dimensional spaces. At the same time, these dimensions have a special interpretation in physics. 

What fascinates you most about working on theoretical rather than applied mathematics?

My motivation often comes out of curiosity and my belief that the solutions to the problems will become useful at some point in the future. But it is not my job to judge or to define the usefulness. My belief is that the fundamental questions must be answered, so that other people can use this knowledge later. It is important to understand the phenomena in mathematics and in science in general, and the possibility of discovering something that other people have not yet. Maybe it is possible to come up with other ideas for detectors, which become interesting. When I look at physics detectors, for example, it fascinates me how complex these machines are and how many tiny technical solutions must be invented to make it all work. 

How did you go about cracking the sphere-stacking problem? 

I think there was an element of luck that I could find the correct idea to solve this problem because many people worked on it before. I was fortunate to find the right solution. The initial problem came from geometry, but the final solution came from Fourier analysis, via a method called linear programming. 

I think a mathematical reality exists on its own and sometimes it does describe actual physical phenomena

In 2003, mathematicians Henry Cohn and Noam Elkies applied the linear programming method to the sphere-packing problem and numerically obtained a nearly optimal upper bound in dimensions 8 and 24. Their method relied on constructing an auxiliary, “magic”, function. They computed this function numerically but could not find an explicit formula for it. My contribution was to find the explicit formula for the magic function.

What applications does your work have, for example in quantum gravity? 

After I solved the sphere-packing problem in dimension 8 in 2016, CERN physicists worked on the relation between two-dimensional conformal field theory and quantum gravity. From what I understand, conformal field theories are mathematically totally different from sphere-packing problems. However, if one wants to optimise certain parameters in the conformal field theory, physicists use a method called “bootstrap”, which is similar to the linear programming that I used. The magic functions I used to solve the sphere-packing problem were independently rediscovered by Thomas Hartman, Dalimil Mazác and Leonardo Rastelli.

Are there applications beyond physics?

One of the founders of modern computer science, Claude Shannon, realised that sphere-packing problems are not only interesting geometric problems that pure mathematicians like me can play with, but they are also a good model for error-correcting codes, which is why higher-dimensional sphere packing problems became interesting for mathematicians. A very simplified version of the original model could be the following. An error is introduced during the transmission of a message. Assuming the error is under control, the corrupted message is still close to the original message. The remedy is to select different versions of the messages called codewords, which we think are close to the original message but at the same time far away from each other, so that they do not mix with each other. In geometric language, this situation is an exact analogy of sphere-packing, where each code word represents the centre of the sphere and the sphere around the centre represents the cloud of possible errors. The spheres will not intersect if their centres are far away from each other, which allows us to decode the corrupted message.  

Do you view mathematics as a tool, or a deeper property of reality?

Maybe it is a bit idealistic, but I think a mathematical reality exists on its own and sometimes it does describe actual physical phenomena, but it still deserves our attention if not. In our mathematical world, we have chances to realise that something from this abstract mathematical world is connected to other fields, such as physics, biology or computer science. Here I think it’s good to know that the laws of this abstract world often provide us with useful gadgets, which can be used later to describe the other realities. This whole process is a kind of “spiral of knowledge” and we are in one of its turns.

The post Playing in the sandbox of geometry appeared first on CERN Courier.

In addition to describing the nature of their work and the skills acquired at CERN that have helped them make the transition, the panellists explained which new skills they had to develop after CERN for a successful career move. The around 180 participants who attended the online event received tips for interviews and CV-writing and heard personal stories about how a PhD prepares you for a career outside academia. 

The panellists agreed that metrics used in academia to qualify a person’s success, such as a PhD, the h-index, or the number of published papers, do not necessarily apply to roles outside of academia, except for research positions. “You don’t need to have a PhD or a certificate to demonstrate that you are a good problem solver or a good programmer – you should do a PhD because you are interested in the field,” said Cristina Bahamonde, who used to work in accelerator operations at CERN and now oversees and unblocks all Google’s network deployments as regional leader for its global network delivery team in Europe, the Middle East and Africa. She considers her project-management and communication skills, which she acquired during her time at CERN while designing solution and mitigation strategies for operational changes in the LHC, essential for her current role. 

General skills needed for big-tech companies include the ability to learn and adapt fast, project and product-management skills, as well as communicating effectively to technical and non-technical audiences. Some participants were unaware that skills that they sharpened intuitively throughout their academic career are vital for a career outside.

“CERN taught me how to be a generalist,” says James Casey, now a group programme manager at Microsoft. “I was not working as a product manager at CERN, but you do very similar work at CERN because you write documents, build customer relationships and need to communicate your work in an understandable way as well as to communicate the work that needs to be done.” At CERN in 1994, Casey worked as a summer student alongside the original team that developed the web. After having worked in start-ups, he returned to CERN for a while and then moved back to industry in 2011.

Finding the narrative

Finding your own narrative and presenting it in the right way on a resumé is not always easy. “When I write my resumé, it looks really straight forward,” said Mariana Rihl, former LHCb experimentalist and now Meta’s product-system validation lead for verifying and validating Oculus VR products. “But only after a certain time, I realised that a common theme emerged — testing hardware and understanding users’ needs.” Working on the LHCb beam-gas vertex detector and especially ensuring the functionality of detector hardware prepared her well, she said. 

Former CERN openlab intern Ritika Kanade, who now works as a software engineer at Apple, shared her experience of interviewing people applying for software engineering roles. “What I like to see during an interview is how the applicant approaches the tasks and how he or she interacts with me. It’s ok if someone needs help. That’s normal in our job,” she adds. “Time management is one thing I see many candidates struggle with.” Other skills needed in industry as well as in academia are tenacity and persistence. Often, candidates need to apply more than three times to land a job at their favourite company. “I applied six or seven times before I was invited for an interview at Google,” emphasised Bahamonde.

The Moving out of academia series provides a rich source of advice for those seeking to make a career change, with the latest event following  others dedicated to careers in finance, industrial engineering, big data, entrepreneurship, the environment and medical technologies. “This CERN Alumni event demonstrated once more the impact of high-energy physics on society and that people transitioning from academia to industry bring fresh insights from another field,” said Rachel Bray, head of CERN Alumni relations.

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Receiving a doctorate from the University of Freiburg in 1956 under the tutelage of Wolfgang Gentner, Soergel remained at Freiburg until 1961, with a year at Caltech in 1957–1958. He then joined CERN as a research associate, working with Joachim Heintze on the beta decay of elementary particles, especially very rare decays of mesons and hyperons. Their results became milestones in the development of the Standard Model, resulting in the award of the German Physical Society’s highest honour in 1963.

In 1965 Soergel became a professor at the University of Heidelberg. He continued his research at CERN while taking on important roles at the university: as director of the Institute of Physics, as dean and as a member of the university’s administrative council. With vision and skill, he played a major role in shaping the university.

Important tasks outside Heidelberg followed. From 1976–1979 he chaired the DESY Scientific Council through a period that saw work begin on the electron–positron collider, PETRA. Under his leadership, the council played an important role in DESY’s transition from national to international laboratory. In 1979 and 1980 he served as research director at CERN, helping pave the way for the collider experiments of the 1980s.

From 1981–1993 Soergel headed DESY, overseeing construction of the electron–proton storage ring, HERA, together with Björn Wiik and Gustav-Adolph Voss. HERA and its experiments benefited from large international contributions, mainly in the form of components and manpower: an approach that became known as the HERA model. Soergel’s powers of persuasion, his reputation, and his negotiating skills led to support from institutes in Western Europe, Israel and Canada, as well as from Poland, Russia and China. From 1996–2000 he headed the Max Planck Institute for Physics in Munich. Under his guidance, photon science became an important pillar of DESY research, first as a by-product of accelerators used for particle physics, then, with the inauguration of HASYLAB in 1981 and the conversion of DORIS, as an established research field that continues strongly to this day. 

Soergel’s time at DESY coincided with German reunification. He enabled the merger of the Institute for High Energy Physics in Zeuthen, near Berlin, with DESY and, together with Paul Söding, made Zeuthen a centre for astroparticle physics. Even before the Iron Curtain fell, Soergel personally ensured that Zeuthen scientists could work at DESY.

Volker Soergel received many honours. He was awarded the Federal Cross of Merit, 1st class, and honorary doctorates from the universities of Glasgow and Hamburg. He has left a lasting legacy. His love for physics was similar in intensity to his love for music. A gifted violin and viola player, he enjoyed making music with his wife and children, friends and colleagues. All who worked with him remain grateful for all they learned from him and will not forget his support and guidance. 

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Nicola was a leading authority on the use of mathematics in high-energy theoretical physics. At Rockefeller, his research focused on the mathematical description of elementary-particle collisions. Among his most notable achievements were the introduction of a new method to study the Riemann hypothesis, one of the last unsolved problems in mathematics, and the foundation of the field of potential scattering theory, which led to the development of important concepts such as Regge poles and strings. 

In addition to his post at Rockefeller, he held visiting appointments and consulting roles at CERN, Stanford University, Columbia University, Lawrence Livermore National Laboratory, Brookhaven National Laboratory and Los Alamos National Laboratory. He was also a member of the panel on national security and arms control of the Carnegie Endowment for International Peace and a fellow of the American Physical Society.

Nicola and Liz, along with their two children, built a beautiful life in New York. Their homes had a revolving door for friends, family, colleagues and mentees who came from far and wide to hear Nicola’s remarkable stories, take in his sage advice, and enjoy his timeless, occasionally risqué jokes. A true cosmopolitan, he relished the vibrancy and possibility of New York. When not at home, he could be found ordering mezze for the table at one of his favourite Lebanese restaurants, exploring his interest in international politics at the Council on Foreign Relations, or making a toast at the Century Association. He retained an enduring love for, and a fundamental commitment to, Lebanon. He was a passionate supporter of his alma mater, a mentor to generations of young scientists from the Middle East, and was instrumental in establishing the university’s Center for Advanced Mathematical Sciences, among many other contributions.

There are many things we will miss about Nicola: his character; the way he commanded a room; his childlike sense of humour; the happy gleam in his eye when he told a story from his adventurous life; and his sneaky determination in old age to satisfy a lifelong appetite for good wine, good cheese and excellent chocolate over the protests of doctors, caregivers and his daughter, Suzanne. Above all, we will miss the way he treated others. 

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Valery Rubakov, who pioneered groundbreaking ideas and methods in many domains of particle physics and cosmology, passed away suddenly on 19 October at the age of 67. 

Born in Moscow in 1955, Valery studied physics at Moscow State University from 1972–1978. He started doing research in his third year of studies, publishing his first paper at the age of 21 on the topic of quantum gravity. Valery joined the Institute for Nuclear Research (INR) of the Russian Academy of Sciences in 1978, defending his PhD on the non-perturbative aspects of gauge theories in 1981. At the age of 26, Rubakov had already made his name in global high-energy physics. He discovered that the ’t Hooft–Polyakov super-heavy magnetic monopoles that exist in grand-unified theories “catalyse” proton decay – a beautiful and subtle non-perturbative effect that provides alternative experimental signatures in the search of monopoles. 

Valery was one of the first physicists to realise the importance of inflationary theory, his 1982 work with Mikhail Sazhin and Alexey Veryaskin on the primordial production of gravitational waves establishing important constraints on the energy scale of the de-Sitter stage of inflation. In 1983 Rubakov (together with Mikhail Shaposhnikov) proposed alternatives to Kaluza–Klein compactification in theories with more than four space–time dimensions – one of which is now known as the brane-world scenario, where the particles of our world live on a four-dimensional defect embedded in a higher-dimensional universe. 

He produced key contributions towards the understanding of the baryon asymmetry of the universe. His paper in 1985 with Vadim Kuzmin and Shaposhnikov revealed that non-perturbative processes can drive a rapid violation of baryon- and lepton-number conservation in the early universe – the basic ingredient of thermal leptogenesis. In 1998, together with Evgeny Akhmedov and Alexey Smirnov, he suggested how to produce the baryon asymmetry by relatively light right-handed neutrinos – an alternative to so-called Fukigita–Yanagida leptogenesis, which opened a unique possibility for experimental verification. 

In a series of remarkable articles from 1987–1988, Valery, together with his PhD students George Lavrelashvili and Peter Tinyakov, discussed the physical impact of topology change in quantum gravity, analysing deep conceptual issues such as quantum coherence. In 1990–1991, together with Sergei Khlebnikov and Peter Tinyakov, he attacked the challenging problem of how to compute the probability of anomalous processes with baryon number non-conservation in very high-energy collisions above tens of TeV. He returned to this problem together with Fedor Bezrukov, Dmitry Levkov and Claudio Rebbi, in 2003, demonstrating that these reactions are exponentially suppressed, thus removing hopes of experimental verification of this phenomenon. 

Valery made imprints in virtually all areas of particle physics and cosmology: supersymmetry phenomenology; the strong CP-problem; dark matter and dark energy; non-commutative field theories; classical and quantum gravity; and alternatives to inflation, to name a few. His very last article, written with Christof Wetterich, was devoted to a physical concept of time for the beginning stage of the universe.

Valery was also an outstanding and passionate teacher, creating the “Rubakov School” of theo­retical physics and cosmology in Moscow, and a successful scientific manager. As a research director of INR from 1987 to 1994, for example, he was responsible for the construction and operation of the Baksan neutrino observatory and the Baikal deep underwater neutrino telescope. Valery was a member of the CERN Scientific Policy Committee from 2014 to 2019 and served on the ICTP Scientific Council from 2010 to 2020. He was the recipient of numerous prizes, awards and distinctions and wrote several excellent textbooks, including Classical Theory of Gauge Fields (Princeton 2002).

Valery Rubakov was an exceptional person. He defended scientific thinking, the freedom of mind and fruitful collaboration between scientists from different countries. He will always be remembered for his kindness, sharp and inventive mind, charisma, honesty and integrity.

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Kurt Gottfried, professor emeritus at Cornell University and co-founder of the Union of Concerned Scientists (UCS), passed away on 25 August 2022 at the age of 93. Throughout his career, he encouraged fellow scientists to hold their leaders to account on topics ranging from nuclear arms control to human rights and scientific integrity. 

Gottfried was born in Vienna, Austria in 1929, fleeing the country with his family when he was nine years old after their home was raided on Kristallnacht, and eventually immigrating to Montreal, Canada. He graduated from McGill University, earned a PhD in theoretical physics from MIT in 1955 and was a junior fellow at Harvard. In 1964 he became a physics professor at Cornell and remained affiliated with the university until his death. He also served on the senior staff of CERN, as a chair of the division of particles and fields of the American Physical Society, and as a member of the American Academy of Arts and Sciences, and the Council on Foreign Relations. 

Well known for his work in high-energy theo­retical physics and the foundations of quantum mechanics, Gottfried worked with David Jackson in the 1960s on the production and decay of unstable resonances in hadronic collisions using the density-matrix approach. He proposed the Gottfried sum rule for deep inelastic scattering and is also known for his work in the 1970s on charmonium. Along with Tung-Mow Yan, he authored the classic work Quantum Mechanics: Fundamentals, originally published in 1966.

In 1969, deeply concerned about what he saw as the growing threat to civilisation from the unchecked exploitation of scientific knowledge for military purposes, Gottfried co-founded UCS with his friend and future Nobel laureate Henry Kendall. His many years of leadership and guidance helped expand the scope of the organisation’s work from research on nuclear power and weaponry, to climate change, agriculture, transportation and renewable energy. Even in retirement, Gottfried continued to advise UCS scientists on policy and strategy, and to inspire the organisation with his passionate sense of urgency about its work.

In the 1980s, working with Hans Bethe and Richard Garwin, Gottfried drew attention and acclaim to UCS by demonstrating the infeasibility of the “Star Wars” missile defence programme. He authored numerous scholarly articles on missile defence, space weapons, nuclear weapons and cooperative security, and reached an even wider audience with his articles and op-eds on these topics. He also authored or co-authored three books – The Fallacy of Star Wars (1984), Crisis Stability and Nuclear War (1988) and Reforging European Security: From Confrontation to Cooperation (1990) – and contributed chapters to several others.

Throughout his life, Gottfried also used his standing to advocate for the free practice of science. In addition to his work with UCS, he was deeply engaged in campaigns in support of scientists in the former Soviet Union and South America who were imprisoned for expressing views in conflict with the dogmas of authoritarian rulers. In 2016, citing his long and distinguished career as a “civic scientist”, the American Association for the Advancement of Science awarded Gottfried its Scientific Freedom and Responsibility Award.

As current UCS board chair Anne Kapuscinski noted, Kurt was the epitome of a concerned scientist and an inspiration to all of us. We will miss his passion, kindness, dedication and integrity, and we will strive to honour his lifelong dedication to building a safer world.

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UK experimental particle physicist Don Perkins, who played a significant role in shaping the field from the 1940s onwards, passed away on 30 October at the age of 97. 

After graduating from Imperial College, London, Perkins obtained a PhD under the supervision of George Paget Thomson, recipient of the 1937 Nobel Prize in Physics. As part of his thesis work, he took a photographic emulsion – a new medium for particle detection at the time – onto a Royal Air Force transport plane to record cosmic rays at altitude. This resulted in what was later recognised to be the first observation of the pion, published in Nature in 1947.

In 1951 Perkins joined another Nobel laureate, Cecil Powell, in Bristol where, working with Peter Fowler, he discovered some of the decay properties of pions. This involved touring some of the world’s mountain tops with photographic emulsions, as well as sending them into the stratosphere on balloons. As a result of their studies, Perkins and Fowler were the first to suggest that irradiation with negatively charged pions might be used to treat cancer. In 1965 Perkins moved to the University of Oxford where, under the overall leadership of Denys Wilkinson, he established a world-leading particle-physics group. One year later he was elected a Fellow of the Royal Society. In 1991 he received the Royal Medal of the Royal Society, among many honours that would crown his long career. 

As modern electronic counters and bubble chambers began to replace emulsion techniques, Perkins worked at CERN, where in 1973 he contributed to the seminal discovery of neutral currents with the Gargamelle bubble chamber. Thirty years later, in characteristic style and peppered with anecdotes, Perkins recounted the story of the neutral-current discovery in this magazine (CERN Courier Commemorative Issue Willibald Jentschke June 2003 p15). 

In the late 1960s, when the scattering of electrons off protons in experiments at SLAC had established that the proton is not elementary, Perkins realised that neutrino scattering could give complementary information that helped prove the existence of fractionally charged quarks. He was also an early supporter of quantum chromodynamics, which explained why quarks are confined inside hadrons. 

As the 1970s progressed, Perkins became increasingly interested in proton decay, and was a leading advocate of the Soudan-II experiment in the US. Although Soudan-II never saw evidence of proton decay, the experiment made important contributions to advancing the field of neutrino physics.

Over his long career, Perkins’ brilliance benefitted generations of physics students, many of whom were drawn to particle physics through his textbook Introduction to High Energy Physics, first published in 1972 based on his undergraduate lectures and now in its fourth edition. Besides his experimental and theoretical contributions, Perkins was active in the governance of particle physics, having chaired both the nuclear physics board of the UK’s former Science and Engineering Research Council and CERN’s Scientific Policy Committee. He was a member of many international advisory committees and strategy meetings, including one in 1979 that led to the construction of the HERA electron–proton collider at DESY.

A charismatic and influential figure, his wisdom, delivered in a northern English accent and accompanied by his distinctive laugh, will be greatly missed by his many friends and colleagues.

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On 7 September colleagues and friends of Gabriele Veneziano gathered at CERN for an informal celebration of the renowned theorist’s 80th birthday. While a visitor in the CERN theory division (TH) in 1968, Veneziano wrote a paper “Construction of a crossing-simmetric, Regge-behaved amplitude for linearly rising trajectories”. It was an attempt to explain the strong interaction, but ended up marking the beginning of string theory. During the special TH colloquium, talks by Paolo Di Vecchia (NBI&Nordita), Thibault Damour (IHES) and others explored this and numerous other aspects of Veneziano’s work, much of which was undertaken during his 30 year-long career at CERN. Concluding the day’s proceedings, Veneziano thanked his mentors, CERN TH and chance – “the chance of having lived through one of most interesting periods in the history of physics… during which, through a wonderful cooperation between theory and experiment, enormous progress has been made in our understanding of nature at its deepest level.”

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In school I liked and did well in science and math. I liked the feeling of certainty of math. There is an objective truth in math. And I was fascinated by the fact that I could use math to describe physical phenomena, to capture the complexity of the world in elegant mathematical equations. I also had an excellent, rigorous high-school physics teacher, whom I admired. 

Accelerators offered the possibility of addressing fundamental challenges in (accelerator) physics and technology, and getting verifiable results in a reasonable amount of time to have a material impact. In addition, particle accelerators enable research and discovery in a vast range of scientific fields (such as particle and nuclear physics, X-ray and neutron science) and societal applications such as cancer treatment and radioisotope production.

What was your thesis topic? 

My PhD thesis tackled experimentally, theoretically and via computer simulations the nonlinear dynamics of transverse particle oscillations in the former Tevatron collider at Fermilab, motivated by planning for the Superconducting Super Collider. Nonlinearities were introduced in the Tevatron by special sextupole magnets. In a series of experiments, we obtained accurate measurements of various phase–space features with sextupoles switched on. One of the features was the experimental demonstration of “nonlinear resonance islands” – protons captured on fixed points in phase space.

What have been the most rewarding and challenging aspects of your career so far?

There are many rewarding aspects of what I do. Seeing an audience, especially young people, who light up when I explain a fascinating concept. Pointing to something tangible that I contributed towards that will enable scientists to make discoveries in accelerator, particle or nuclear physics. Having conceived, worked on and advocated certain types of accelerators and seeing them realised. Predicting a behaviour of the particle beam, and verifying it in experiments. Also, troubleshooting a serious problem, and after days and nights of toil, finding the origin of or solution to the problem. 

In terms of challenges, at Fermilab right now we are working on very complex and challenging projects like LBNF/DUNE. It involves more than 1400 international collaborators preparing and building a technically complex endeavour almost one mile underground. The mere scale of the operation is enormous but the pay-off is completing something unprecedented and enabling groundbreaking discoveries.

What are your goals as Fermilab director?

First and foremost, the completion of LBNF/DUNE to advance neutrino physics. Also, the completion of the remainder of the 2014 “P5” programmes, including the HL-LHC upgrades of the accelerator and CMS detector, and a new experiment at Fermilab called Mu2e. Looking to the future, when the next P5 report is completed, we will launch the next series of projects. Quantum technology is also a growing focus. Fermilab hosts one of five national quantum centres in addition to being a partner in a second one. We utilise our world-leading expertise in superconducting radiofrequency technology and instrumentation/control to advance quantum information technologies, as well as conducting unique dark-matter searches using this expertise. 

Is being director different to what you imaged?

It takes a lot of hard work to build an excellent team, exceeding my initial projection. But equally our staff’s commitment, good will and dedication have also exceeded my expectations.

Which collider should follow the LHC, and what is the role of the US/Fermilab in realising such a project? 

No matter which collider is chosen, there is still a lot of R&D required for any path concerning magnets, radiofrequency cavities and detectors. This R&D is crucial to multiple applications. I would advocate the development of these capabilities to push the state of the art for accelerators and detectors in the near future. Future colliders are an important component of the current Snowmass/P5 community planning exercise. Here, Fermilab is aligned with the previous P5 and is committed to following the next P5 recommendations.

How would you describe high-energy physics today compared to when you entered the field?

In the 1980s, the major building blocks of the Standard Model were largely in place, and the focus of the field was to experimentally verify many of its predictions. Today, the Standard Model is much more thoroughly tested, but there is evidence that it does not completely describe the whole picture. 

The upcoming century promises a fascinating array of ground-breaking discoveries

A lot of present-day research is about physics beyond the Standard Model, including dark matter, dark energy and the question of matter–antimatter asymmetry in the universe. In parallel, technologies have advanced tremendously since the 1980s, enabling unprecedented precision, parameter reach and new discoveries. This applies to accelerators, telescopes, detectors and computing. The upcoming century promises a fascinating array of groundbreaking discoveries, all of which will fundamentally further our understanding of the universe. 

What can be done to ensure that there are more female laboratory directors worldwide?

I think it is important to increase the pipeline, starting with efforts to attract young people in elementary and high school. We need to look at changing the cultural perspective that women can’t do STEM and get to the point where the entire culture is open-minded. We also need to change the make-up of the committees. 

It is important to encourage females to take on leadership positions and then support and empower them with enlightened mentors. Once they develop their careers, we will have a much bigger pool for future lab directors. We must inspire and empower young girls and women to follow their dreams, and help them stay focused to succeed. 

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Alain Magnon, a well-known French nuclear physicist and long-serving spokesperson of the COMPASS collaboration at CERN (2003–2010), passed away on 18 March 2022. Retired from IRFU CEA Saclay for more than 10 years, he remained an enthusiastic COMPASS member, valuably participating in the activities of the Illinois and Matrivani groups. In recent years he was an active contributor to the Physics Beyond Colliders working group and to the MUonE project at CERN. 

After graduating as an engineer from the École centrale des arts et manufactures in Paris in the late 1960s, Alain joined the nuclear physics division at Saclay where he worked on the first prototypes of multi-wire proportional chambers. Interested in continuing his career as a nuclear physicist, he later moved to the University of Chicago to carry out his PhD thesis work on the hyperfine structure of muonium, under the supervision of Val Telegdi. 

Returning to Saclay, Alain played a leading role in measurements of the muon lifetime and capture rates, resulting in one of the most precise determinations of the Fermi weak-coupling constant. These measurements were later extended to both positive and negatively charged muons using an ultra-pure liquid hydrogen target. Mastering advanced cryogenic and vacuum technologies, Alain worked hard to reduce the impurity level of the target to negligible values. He also participated in one of the earliest measurements of the pion electromagnetic radius in coincidence (e, e′π) experiments. Later, Alain contributed to one of the first experiments on parity-violation at the MIT–Bates accelerator under the direction of Vernon Hughes. As a member of the (e, e′p) group at Saclay, he devoted great efforts to measuring the proton form factor within the ⁴⁰Ca nucleus, providing evidence that the bound nucleon form factor has the same Q² dependence as that of the free nucleon. 

At the beginning of the 1990s, Alain switched to high-energy muon scattering. He made important contributions to the SMC polarised target and served as the contact for the collaboration. Later, he became one of the founding members of the COMPASS experiment. As head of the Saclay group, he proposed and led the project for the construction of large-sized drift chambers. He also coordinated the crucial Saclay–CERN work to repair and test the COMPASS large-acceptance superconducting magnet. Project and group leader, accomplished detector expert and tenacious spokesperson, Alain Magnon played an essential role in the success of COMPASS as a unique experiment and as a renowned international collaboration.

All of his colleagues and friends will miss Alain and his rigorous and resolute approach to instrumentation and scientific research.

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Announced on 4 October, the 2022 Nobel Prize in Physics has been awarded to Alain Aspect, John Clauser and Anton Zeilinger for groundbreaking experiments with entangled photons that open a path to advanced quantum technologies. Working independently in the 1970s and 1980s, their work established the violation of Bell inequalities – as formulated by the late CERN theorist John Bell – and pioneered the field of quantum information science.

First elucidated by Schrödinger in 1935, entanglement sparked a long debate about the physical interpretation of quantum mechanics. Was it a complete theory, or was the paradoxical correlation between entangled particles due to hidden variables that dictate in which state an experiment will find them? In 1964 John Bell proposed a theorem, known as Bell’s inequalities, that allowed this question to be put to the test. It states that if hidden variables are in play, the correlation between the results of a large number of measurements will never exceed a certain value; conversely, if quantum mechanics is complete, this value can be exceeded, as measured experimentally.

John Clauser (J F Clauser & Associates, US) was the first to investigate Bell’s theorem experimentally, obtaining measurements that clearly violated a Bell inequality and thus supported quantum mechanics. Alain Aspect (Université Paris-Saclay and École Polytechnique, France) put the findings on even more solid ground by devising ways to perform measurements of entangled pairs of photons after they had left their source, thus ruling out the effects of the setting in which they were emitted. Using refined tools and a long series of experiments, Anton Zeilinger (University of Vienna, Austria) used entangled states to demonstrate, among other things, quantum teleportation. 

These delicate, pioneering experiments not only confirmed quantum theory, but established the basis for a new field of science and technology that has applications in computing, communication, sensing and simulation. In 2020 CERN joined this rapidly growing global endeavour with the launch of the CERN Quantum Technology Initiative. 

Foundational work in quantum-information science was also the subject of the 2023 Breakthrough Prize in Fundamental Physics, announced in September, for which Charles H Bennett (IBM), Gilles Brassard (Montréal), David Deutsch (Oxford) and Peter Shor (MIT) will receive $3 million each.

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On 16 August 2022, pioneering theorist Harald Fritzsch unexpectedly died at the age of 79. His essential contributions to the development of quantum chromodynamics and the grand unification of the fundamental forces made a lasting and profound impact on the field of theoretical physics.

Harald Fritzsch was born on 10 February 1943 in Zwickau, Germany. He studied physics and completed his diploma thesis at Leipzig University in June 1968. At this time, he had already contemplated leaving the German Democratic Republic (GDR) and so sent his diploma thesis to Werner Heisenberg in Munich. In 1968, in an adventurous and dramatic escape by boat across the Black Sea from the Eastern Block to Turkey, Fritzsch and a friend fled the GDR and relocated to the Federal Republic of Germany. Fritzsch went straight to Munich, where Heisenberg accepted him as a doctoral student in his research group at the Max Planck Institute for Physics. His thesis, supervised by Heinrich Mitter and completed in 1971, dealt with light-cone algebra and the quantisation of the strong interaction. In 1970 Fritzsch received a DAAD scholarship for a six-month stay at SLAC and met Murray Gell-Mann for the first time, in Aspen.

After receiving his doctorate, Fritzsch spent a year as a research fellow at CERN, followed by four years as a senior research associate at Caltech. The collaboration between Fritzsch and Gell-Mann continued and led to groundbreaking work on the strong interaction. In 1977 Fritzsch followed a call as professor at the University of Wuppertal, which changed to become the University of Bern. Then, in 1979, he became Ordinarius at Ludwig Maximilian University in Munich.

In 1971 Fritzsch and Gell-Mann introduced the colour quantum number as the exact symmetry underlying the strong interactions, thereby solving the long-standing problem of preserving the exclusion principle as discussed, for example, by Han and Nambu in 1965. A year later, Fritzsch and Gell-Mann proposed a Yang–Mills gauge theory with local colour symmetry, which is now called quantum chromodynamics (QCD). This new idea was first presented by Gell-Mann in the fall of 1972 at a conference in Chicago, and then in a joint conference paper by Fritzsch and Gell-Mann. In 1973 their famous paper on the colour-octet model of QCD, now also with Heinrich Leutwyler, appeared in Physics Letters. This publication, together with the papers by Gross, Politzer and Wilczek about asymptotic freedom in non-Abelian gauge theories, all published in the same year, is regarded as the beginning of QCD. 

Fritzsch wrote many other scientific papers that are of great importance for theoretical particle physics, for example on SO(10) grand-unification, weak interactions, the famous Fritzsch mass matrices and composite models. For his significant scientific achievements, he was awarded the Dirac Medal of the University of New South Wales in Australia in 2008. He was a member of the Society of German
Natural Scientists and Physicians, and of the Berlin–Brandenburg Academy of Sciences. In 2013 he was awarded an honorary doctorate from Leipzig University. 

Fritzsch is also widely known as an author of popular scientific books. His book Quarks, published in 1980, was translated into more than 20 languages, and in 1994 he was awarded the Medal for Scientific Journalism of the German Physical Society. 

In addition to his outstanding scientific achievements, we also admired Harald for his strong, determined, honest and straightforward mind, and for his courage to express his sound opinions and to tackle problems and disputes, even if inconvenient to some. 

Until the very end, Harald was seen in his university office almost every day. He will be sadly missed, but never forgotten.

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How is Finden helping the big-science community to grow its industry user base?

As a regular user of large-scale synchrotron facilities within Europe, we enable our industry customers to fast-track R&D projects through unique measurement capabilities tailored to their needs. Put simply, Finden helps industry clients to solve complex materials problems that they’re unable to solve on their own. It’s a winning formula: many of our customers come back to us on a serial basis, tapping the collective expertise of the Finden team and the streamlined access we provide to Europe’s synchrotron light sources.

What do you mean by streamlined access?

There are often significant logistics overheads when it comes to finding and securing beam time at a synchrotron facility – a barrier to direct industry engagement with big science. At Finden, we have the know-how, as well as an extensive network of contacts within the synchrotron community, to take care of all the associated “legwork” for our clients, matching the right beamline and scientific instruments to the industrial problem at hand. That translates into express workflows and turnaround – the key to successful delivery of high-end materials characterisation services for industrial problem-solving.

Operationally, how do new industry clients engage with Finden?

For the most part, our client base comprises established companies rather than small and medium-sized enterprises. First contact can happen in a variety of ways: an exploratory conversation with a Finden scientist at a conference, for example, or sometimes a synchrotron facility may point an industry enquiry in our direction. Once the dialogue is under way, we’ll meet with the client to understand their materials problem at a granular level – often under a non-disclosure agreement to ensure commercial confidentiality. My task as managing director is to make sure we’ve got all the right people in the room from Finden to establish the appropriate characterisation methods versus the client’s problem and specified timeline – as well as an accurate financial quotation for the plan of work. 

Do all of the industry problems you tackle require synchrotron beam time?

Not all of them. We have access to a suite of powerful materials analysis techniques here on the Harwell campus (in Oxfordshire) and those lab-based tools often represent a cheaper and more efficient option for our industry clients. When we do engage with the large-scale facilities – for example, the nearby Diamond Light Source or the European Synchrotron Radiation Facility (ESRF) in Grenoble – we make all the necessary arrangements and carry out the work on behalf of the client. Sometimes our scientists will conduct materials studies at the synchrotron beamline – “eyes on the sample” so to speak – though even when working remotely the team will be conducting on-the-fly data analysis and liaising throughout with scientists and technicians in situ. 

What does the business model look like for the provision of these big-science services?

It might seem counter-intuitive, but we don’t charge a premium for synchrotron beam time. That’s all billed at-cost to mitigate the chance of the customer going direct to the synchrotron. Our differentiation – and where we make our money – lies in the collective expertise of the Finden team in synchrotron science, instrumentation and techniques – not least our capabilities across experimental design, data analysis and interpretation. By extension, one of the growth opportunities we’re now pursuing is the application of machine-learning and deep-learning technologies to high-throughput data analysis. It’s early days, but we’re already securing industry contracts that tap this capability exclusively, including projects that do not require any experimental data collection on our part. 

How is Finden structured right now?

Finden is really two parallel and complementary businesses under one roof. The mediator company, which provides specialist materials science capabilities to industry, rents laboratory space and equipment across the Harwell Innovation Campus on an as-needed basis, while developing a pipeline of higher-level characterisation projects that require access to Europe’s synchrotron light sources. Alongside the science-service business, we run our own dedicated research laboratory that we lease from the Science and Technology Facilities Council, a UK government funding agency. This lab is largely ring-fenced for in-house R&D and innovation initiatives under the broad themes of catalysis and machine learning – essentially longer-term bets with a view to building sustainable royalty and licensing revenues from the associated intellectual property portfolio.

What do the growth opportunities look like for Finden?

Diversification is very much part of Finden’s development roadmap. Right now, the heart of our business is materials characterisation using diffraction, spectroscopy and imaging techniques spanning conventional X-ray and synchrotron science. Conceptually, it’s a logical progression to apply those transferable capabilities to other modalities used in fundamental and applied materials research. In summary: expect to see Finden scientists tackling industry’s R&D problems at large-scale neutron and laser facilities in the not-too-distant future. 

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François Piuz, a talented and passionate CERN physicist since 1968 who was leader of several projects, passed away on 21 July 2022 aged 85. Throughout his distinguished career, François worked at the forefront of particle detectors. With his many talents, he made significant contributions to topics ranging from the fundamental principles of detector operation to the innovative technologies required to deploy detectors in large experiments. 

François began his scientific journey in the early 1970s as a notable member of the team that transformed the invention of the Nobel Prize-winning multi-wire proportional chamber (MWPC) into the system of 50,000 wires for the Split-Field Magnet facility at the CERN Intersecting Storage Rings. At this time, he wanted to understand the functioning of these new detectors at the fundamental, microscopic level. His work on the concept of “ionisation clusters” in the MWPC became a classic and was crucial to the development of particle identification based on multiple measurements of ionisation. One spectacular use of this approach is the X-ray photon detection system of the ALICE experiment’s Transition Radiation Detector at the LHC. Cluster counting is also a candidate technique for high-granularity dE/dx measurements at future colliders.

Another highlight that came from his insightful understanding was the development of a novel drift chamber topology capable of measuring particles with exceptional spatial resolution and multi-track separation, as required for the SPS experiments in the 1980s. During this time, he renewed his interest in particle identification and contributed to pioneering studies demonstrating the outstanding potential of solid cesium iodide (CsI) photocathodes for the detection of Cherenkov photons, which would prove so fruitful in the ALICE experiment’s HMPID (High Momentum Particle Identification Detector) RICH detector. 

In 1992 François was one of the main proponents, and the co-spokesperson, of the RD26 project, which, in six years, had successfully developed the technology to produce large-area (up to 0.3 m²) CsI-based gaseous photon detectors for use in RICH systems operated in heavy-ion collision experiments. This project represented the summit of his outstanding scientific career, in which he coupled his unique expertise in gaseous detectors, developed while working with Charpak, with a passion for photography and, therefore, photon detection. Such technology allowed the construction of the largest CsI-RICH detector ever built and rapidly found applications in other experiments, including NA44 and COMPASS at CERN, HADES at GSI and the Hall A experiment at JLab.

François was a member of the ALICE collaboration from its first days and led the HMPID project until 2000. After his retirement in 2002, he continued to actively participate in the construction, installation and operation of the HMPID, which, nearly two decades after its construction, continues to operate at higher rates for LHC Run 3. François was also involved in coordinating test-beam activities, which were instrumental to the R&D for all ALICE detectors.

François’s remarkable knowledge and ability to envision solutions to complex problems were key to the success of the many detector projects that he worked on. He was always interested in new ideas and ready to provide help and support to colleagues. These qualities, combined with a playful sense of humour, made François a very friendly and charismatic personality. He will be missed by many, but will always be remembered for his great qualities, both as a physicist and as a person, by those who were fortunate enough to have worked closely with him.

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Ben R Mottelson passed away on 13 May aged 95. He will be remembered as an outstanding physicist who played a decisive role in the understanding of atomic nuclei and as an inspiring and warm human being with an engaging and outgoing personality.

Ben Mottelson was born in Chicago in 1926 into a family where his father held a university engineering degree. He finished high school in 1944 and was drafted into the navy, which rapidly recognised the young man’s potential and sent him to Purdue University to train as a naval officer. He completed his bachelor degree there in 1947 and subsequently obtained his PhD from Harvard University in 1950 with Julian Schwinger as his supervisor. He won a Sheldon travel fellowship and chose in 1950 to go to the Niels Bohr Institute in Copenhagen, where he was to remain the rest of his life, becoming a Danish citizen in 1971.

After a number of temporary positions, Ben became a permanent member of CERN’s theoretical study group, which was temporarily established in Copenhagen in 1953–1957 while the Geneva site was being completed. He became a tenured professor at Nordita, then the Nordic Institute for Theoretical (Atomic) Physics, at the Niels Bohr Institute in 1957 and headed Nordita from 1981 to 1983. 

In Copenhagen, he established a close scientific collaboration and friendship with Aage Bohr (1922–2009), the son of Niels Bohr. The pair worked on understanding the structure of atomic nuclei based on an inter-play between collective and single-particle degrees of freedom which, as first pointed out by James Rainwater, might not all be spherical. A consequence of deformation would be the existence of rotational bands, as for molecules, which were discovered experimentally early in the 1950s using Coulomb excitation with the cyclotron at the Niels Bohr Institute. A central question was why the effective moment of inertia of a deformed atomic nucleus is smaller than for a rigid rotor. This was understood by Aage, Ben and David Pines in 1958 as a consequence of the pairing of nucleons leading to an energy gap, in analogy with the pair correlations between electrons in a superconductor. 

In subsequent decades Aage and Ben refined the theoretical description of nuclei with a unified nuclear model that accounted for the variety of nuclear excitations in a coherent fashion, establishing a lively collaboration with experimentalists from all over the world. In 1975 Aage, Ben and James Rainwater were awarded the Nobel Prize in Physics for their work. Ben also received the Atoms for Peace award in 1969.

Ben had a close scientific collaboration and friendship with Aage Bohr, the son of Niels Bohr

The partnership between Aage and Ben was fruitful in spite of their different personalities, Aage being the more reserved and Ben the more outgoing personality. The author of this obituary fondly remembers the pair attending the weekly experimental group meetings and attentively questioning all the speakers, sharing insights and always providing kind inspiration to both young and old. Later, Ben turned his attention to other manifestations of shell structure in mesoscopic systems of atomic clusters and to the properties of cold atomic Bose–Einstein gases. From 1993–1997 he was director of the ECT* theory centre, which he helped establish in Trento, Italy.

Ben Mottelson was an unpretentious, open and engaging family man. Until close to the end he continued to come regularly to the Niels Bohr Institute, attending seminars and scientific events, often to be seen on his bicycle. He will be sorely missed.

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Director-general of the ITER Organization, Bernard Bigot, passed away on 14 May, aged 72. An inspirational leader for more than four decades across multiple fields of science and energy, his personal dedication and commitment to ITER over the past seven years shaped every aspect of the project. While his untimely passing will be felt as a tragic blow to the global fusion community, Bigot’s careful design and preparation of the ITER senior management team in recent years gives reassurance for the project’s continued success. 

Bigot took the helm at ITER in March 2015 at a critical point in the project’s history, when it was experiencing significant difficulties reflecting the managerial challenges inherent in both its complex engineering and its multi­national approach to design, manufacturing and construction. He accepted these challenges with humility and unwavering resolve, proposing a multifaceted plan that transformed the project’s culture. Today, ITER is more than 75% complete and stands as a monumental example of scientific and engineering prowess, and a testimony to the merits of international collaboration. 

Trained as a physical chemist at the École normale supérieure, with a PhD in chemistry, Bigot had a deep understanding of the challenges that went with mastering hydrogen fusion. He was a high-ranking university professor at the École normale supérieure de Lyon, which he helped to establish and then directed for several years. The author of more than 70 publications in theoretical chemistry, Bigot was also in charge of research at the École normale supérieure, director of the Institut de recherche sur la catalyse (a CNRS laboratory specialising in catalysis research) and president of the Maison de la Chimie foundation.

The experience he acquired at the highest levels of the scientific and research establishment – as private secretary to ministers, high commissioner for atomic energy, chairman and CEO of the CEA, and as such the principal interface between France and ITER between 2008 and 2015 – had prepared him for the daunting task of leading a 35-nation, long-term endeavour, as unique in its goals as it is in its organisation and governance. However, the uniqueness of ITER required more than experience in science, the management of large institutions and the oversight of complex construction projects. ITER – particularly at the time Bigot took over – also demanded political finesse and diplomatic subtlety, qualities that he had in abundance. Always ready to exchange with media representatives, politicians, economists, VIPs or general visitors, he knew how to make complex subjects understandable and meaningful. 

He received numerous awards, including his status as a Commander in the French Order of the Legion of Honour, a Commander in the Royal Swedish Order of the Polar Star, an Officer of the French Order of the National Merit, the holder of the Gold and Silver Star in the Japanese Order of the Rising Sun, and the recipient of the China Friendship Award. Beyond these achievements and accolades, he will be remembered as a visionary leader, intensely focused on the enhancement of global society and the desire to leave the world a better place. The greatest honour we can pay is to continue delivering the ITER project with the same unwavering commitment and dedication that he demonstrated to all of us.

Bernard Bigot was a man of duty and service, who placed loyalty above all virtues, a deeply human leader, as demanding of others as he was of himself. He will be deeply missed.

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Leading Soviet particle physicist Boris Ioffe passed away in Moscow on 18 July at the age of 96.

Boris Ioffe was born in Moscow in 1926 into a Jewish family. In the late 1940s he passed Landau’s famous “theoretical minimum” entry exam and in 1949 he graduated frоm Moscow State University with a diploma in theoretical physics. He started his research work under the supervision of Isaak Pomeranchuk. Between 1950 and 1955 Ioffe participated in the original Soviet nuclear-bomb project, at its later stage devoted to the hydrogen bomb. Until 18 July he was the only participant of this project still alive. 

In 1960–1980 Ioffe was one of the leading Soviet particle physicists. He was a pioneer of parity (non-)conservation (with Okun and Rudik, 1957). His work with E Shabalin (1967) provided an impetus for the creation of the Glashow–Iliopoulos–Maiani mechanism. Ioffe’s work on deep inelastic scattering (1969) helped establish the Bjorken scaling and the parton model of Feynman–Bjorken. 

During the later stages of his career, Ioffe focused on quantum chromodynamics and its consequences for the theory of hadrons. His contributions to the theory of baryons are well-known and appreciated worldwide.

Ioffe never abandoned his early research in nuclear physics. In fact, he was an expert nuclear physicist and in the early 1970s was in charge of the physics design of the first commercial nuclear power plant in former Czechoslovakia. Since 1977 he was the head of the ITEP Laboratory for Theoretical physics, where he had a number of PhD students.

All his life Ioffe was a devoted mountaineer. It is hard to name a mountain peak that he had not conquered. His life journey was long, adventurous and misadventurous simultaneously. Ioffe’s memoirs are available both in Russian and English.

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What is LISA? 

LISA (Laser Interferometer Space Antenna) is a giant Michelson interferometer comprising three spacecraft that form an equilateral triangle with sides of about 2.5 million km. You can think of one satellite as the central building of a terrestrial observatory like Virgo or LIGO, and the other two as the end stations of the two interferometer arms. Mirrors at the two ends of each arm are replaced by a pair of free-falling test masses, the relative distance between which is measured by a laser interferometer. When a gravitational wave (GW) passes, it alternately stretches one arm and squeezes the other, causing these distances to oscillate by an almost imperceptible amount (just a few nm). The nature and position of the GW sources is encoded in the time evolution of this distortion. Unlike terrestrial observatories, which keep their arms locked in a fixed position, LISA must keep track of the satellite positions by counting the millions of wavelengths by which their separation changes each second. All interferometer signals are combined on the ground and a sophisticated analysis is used to determine the differential distance changes between the test masses. 

What will LISA tell us that ground-based observatories can’t?

Most GW sources, such as the merger of two black holes detected for the first time by LIGO and Virgo in 2015, consist of binary systems; as the two compact companions spiral into each other, they generate GWs. In these extreme binary mergers, the frequency of the GWs decrease both with the increasing mass of the objects and with increasing distance from their final merger. GWs with frequencies down to about a few Hz, corresponding to objects with masses up to a few thousand solar masses, are detectable from the ground. Below that, however, Earth’s gravity is too noisy. To access milli-Hertz and sub-milli-Hertz frequencies we need to go to space. This low-frequency regime is the realm of supermassive objects with millions of solar masses located in galactic centres, and also where tens of thousands of compact objects in our galaxy, including some of the Virgo/LIGO black holes, emit their signals for years and centuries as they peacefully rotate around each other before entering the final few seconds of their collapse. The LISA mission will therefore be highly complementary to existing and future ground-based observatories such as the Einstein Telescope. Theorists are excited about the physics that can be probed by multiband GW astronomy.

When and how did you get involved in LISA?

LISA was an idea by Pete Bender and colleagues in the 1980s. It was first proposed to the European Space Agency (ESA) in 1993 as a medium-sized mission, an envelope that it could not possibly fit. Nevertheless, ESA got excited by the idea and studies immediately began toward a larger mission. I became aware of the project around that time, immediately fell in love with it and, in 1995, joined the team of enthusiastic scientists, led by Karsten Danzmann. At the time it was not clear that a detection of GWs from ground was possible, whereas unless general relativity was deadly wrong, LISA would certainly detect binary systems in our galaxy. It soon became clear that such a daring project needed a technology precursor, to prove the feasibility of test-mass freefall. This built on my field of expertise, and I became principal investigator, with Karsten as a co-principal investigator, of LISA Pathfinder. 

What were the key findings of LISA Pathfinder? 

Pathfinder essentially squeezed one of LISA’s arms from millions of kilometres to half a metre and placed it into a single spacecraft: two test masses in a near-perfect gravitational freefall with their relative distance tracked by a laser interferometer. It launched in December 2015 and exceeded all expectations. We were able to control and measure the relative motion of the test masses with unprecedented accuracy using innovative technologies comprising capacitive sensors, optical metrology and a micro-Newton thruster system, among others. By reducing and eliminating all sources of disturbance, Pathfinder observed the most perfect freefall ever created: the test masses were almost motionless with respect to each other, with a relative acceleration less than a millionth of a billionth of Earth’s gravitational acceleration. 

What is LISA’s status today?

LISA is in its final study phase (“B1”) and marching toward adoption, possibly late next year, after which ESA will release the large industrial contracts to build the mission. Following Pathfinder, many necessary technologies are in a high state of maturity: the test masses will be the same, with only minor adjustments, and we also demonstrated a pm-resolution interferometer to detect the motion of the test masses inside the spacecraft – something we need in LISA, too. What we could not test in Pathfinder is the million-kilometre-long pm-resolution interferometer, which is very challenging. Whereas LIGO’s 4 km-long arms allow you to send laser light back and forth between the mirrors and reach kW powers, LISA will have a 1 W laser: if you try to reflect it off a small test-mass 2.5 million km away, you get back just 20 photons per second! The instrument therefore needs a transponder scheme: one spacecraft sends light to another, which collects and measures the frequency to see if there is a shift due to a passing GW. You do this with all six test masses (two per spacecraft), combining the signals in one heck of an analysis to make a “synthetic” LIGO. Since this is mostly a case of optics, you don’t need zero-g space tests, and based on laboratory evidence we are confident it will work. Although LISA is no longer a technology-research project, it will take a few more years to iron out some of the small problems and build the actual flight hardware, so there is no shortage of papers or PhD theses to be written. 

How is the LISA consortium organised?

ESA’s science missions are often a collaboration in which ESA builds, launches and operates the satellite and its member states – via their universities and industries – contribute all or part of the scientific instruments, such as a telescope or a camera. NASA is a major partner with responsibilities that include the lasers, the device to discharge the test masses as they get charged up by cosmic rays, and the telescope to exchange laser beams among the satellites. Germany, which holds the consortium’s leadership role, also shares responsibility for a large part of the interferometry with the UK. Italy leads the development of the test-mass system; France the science data centre and the sophisticated ground testing of LISA optics; and Spain the science-diagnostics development. Critical hardware components are also contributed by Switzerland, the Netherlands, Belgium, the Czech Republic, Denmark and Poland, while scientists worldwide contribute to various aspects of the preparation of mission operation, data analysis and science utilisation. The LISA consortium has around 1500 members. 

What is the estimated cost of the mission, and what is industry’s role?

A very crude estimate of the sum of ESA, NASA and member-state contributions may add up to something below two billion dollars. One of the main drivers of ESA’s scientific programme is to maintain the technological level of European aerospace, so the involvement of industry, in close cooperation with scientific institutes, is crucial. After having passed the adoption phase, ESA will grant contracts to prime industrial contractors who take responsibility for the mission. To foster industrial competition during the study phase, ESA has awarded contracts to two independent contractors, in our case Airbus and Thales Alenia. In addition, international partners and member-state contributions often, if not always, involve industry.

What scientific and technological synergies exist with other fields?

LISA will look for deviations from general relativity, in particular the case where compact objects fall into a supermassive black hole. In terms of their importance, deviations in general relativity are a very close cousin of deviations from the Standard Model of particle physics. Which will come first we don’t know, but LISA is certainly an outstanding laboratory for fundamental gravitational physics. Then there are expectations for cosmology, such as tracing the history of black-hole formation or maybe detecting stochastic backgrounds of GWs, such as “cusps” predicted in string theory. Wherever you push the frontiers to investigate the universe at large, you push the frontiers of fundamental interactions – so it’s not surprising that one of our best cosmologists now works at CERN! Technologically speaking, we just started a collaboration with CERN’s vacuum group. In LISA we have a tiny vacuum volume in the region where the test masses are located, and it is full of components and cables. It was a big challenge for Pathfinder, but for LISA we definitely need to understand more. The CERN vacuum group is really interested in understanding this, so we are very happy with this new collaboration. As with LIGO, Advanced Virgo and the Einstein Telescope, LISA is a CERN-recognised experiment.

There is no other space mission with as many papers published about its science expectations before it even leaves the ground

What’s the secret to maintaining the momentum in a complex, long-term global project in fundamental physics? 

The LISA mission is so fascinating that it is “self-selling”. Scientists liked it, engineers liked it, industry liked it, space agencies like it. Obviously Pathfinder helped a lot – it meant that even in the darkest moments we knew we were “real”. But in the meantime, our theory colleagues did so much work. As far as I know, there is no other space mission with as many papers published about its science expectations before it even leaves the ground. It’s not just that the science is inspiring, but the fact that you can calculate things. The instrumentation is also so fascinating that students want to do it. With Pathfinder, we faced many difficulties. We were naïve in thinking that we could take this thing that we built in the lab and turn it into an industrial project. Of course we needed to grow and learn, but because we loved the project so much, we never ever gave up. One needs this mind-set and resilience to make big scientific projects work. 

When do you envision launch? 

Currently it’s planned for the mid-2030s. This is a bit in the future at my age, but I am grateful to have seen the launch of LISA Pathfinder and I am happy to think that many of my young colleagues will see it, and share the same emotions we did with Pathfinder, as a new era in GW astronomy opens up.

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Physicist and historian of science Karl von Meyenn passed away on 18 June 2022 in his hometown of Neuburg an der Donau. Karl was a CERN associate for many years, often to be found in Salle Pauli amongst the archive and library of Wolfgang Pauli, on whom he was one of the world’s leading experts. 

Karl was born in Potsdam in 1937 and began studying physics in Chile, where his parents emigrated. He completed his doctorate in 1971 with Siegfried Flügge in Freiburg im Breisgau, then returned with his wife to Chile and taught at the Pontificia Universidad Católica until the military coup of 1973. Back in Germany, he worked first as a senior assistant to Helmut Reik at the faculty of physics in Freiburg, before specialising in the history of science with Armin Hermann at the Historical Institute of the University of Stuttgart in 1975. From 1985 to 1990 he was a professor of history of science at the Universitat Autònoma in Barcelona, after which he joined Hans-Peter Dürr at the Max Planck Institute for Physics in Munich. He also carried out research at the Institute of Theoretical Physics (with Frank Steiner) at the University of Ulm, and at CERN, where he devoted himself to Pauli’s scientific legacy.

Franca Pauli donated her husband’s scientific writings, library and other items to CERN during the 1960s and 1970s, and CERN took responsibility for safeguarding and making this valuable collection available. The Pauli Committee turned to Karl von Meyenn, who tracked down copies of other letters in public or private ownership, then collated this wealth of material into publishable form. Besides the monumental eight volumes of Pauli correspondence, Karl published a biographical anthology on the great physicists (Die großen Physiker) in 1997–1999, a two-volume selection of Erwin Schrödinger’s correspondence in 2011, and numerous essays, lectures and collaborative books on individual scientists and their interactions in developing new concepts in physics. In 2000 he was awarded the Marc-Auguste Pictet Medal of the Société de Physique et d’Histoire Naturelle de Genève for his work on the history of modern physics. Karl was a member of the Pauli Committee from 1994 and an honorary councillor at ETH Zurich since 2006. The library he leaves in Neuburg is a testimony to his great love of classical culture and broad cultural life. Combining great learning and rigorous scholarship with an engaging curiosity and enthusiasm, Karl was a stimulating and extremely likeable colleague. He will be sadly missed. 

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David Cox, a giant in the world of statistics, passed away earlier this year at the age of 97. As he had been a contributor to PHYSTAT workshops and was a supporter of its activities, a seminar held on 23 March was dedicated to his memory. Brad Efron (Stanford) referred to Cox as the world’s most famous statistician – an assessment confirmed by Cox being the first recipient of the International Prize in Statistics, roughly the equivalent of a Nobel Prize. The citation mentioned a lifelong series of contributions to statistics spanning many subjects. In particular, it emphasised his work on what is now called Cox’s proportional hazards model, which provides a very useful way to implement regression analysis of survival times (the times to an event of interest such as the death of a person or failure of a machine). His contribution is ranked 16th in Nature’s list of most-cited papers in any subject.

Heather Battey (Imperial College), who collaborated closely with Cox for the past five years, described how he was still very active until his very last days, and highlighted his helpful and charming personality. 

Long-time collaborator Nancy Reid (Toronto) concurred, admiring his ability to see through extraneous detail and concentrate on the essence of the problem. She remembers going with him to watch Verdi’s Ernani, sung in Italian, in Budapest when they were both attending a statistics meeting there. So that Reid wouldn’t be completely lost, Cox kindly summarised the lengthy and convoluted plot by telling her “The tenor is in love with the soprano, and the baritone is trying to keep them apart.” 

It was a special pleasure to have Cox available at our meetings, and he was always prepared to explain statistical issues in informal discussions with particle physicists. Bob Cousins (UCLA) recalled the talks Cox had given at PHYSTAT meetings in 2005, 2007 and 2011. He compared and contrasted frequentist statistics and the “five faces” of Bayesian statistics, repeatedly warning of the dangers of “treacherous” uniform prior probability densities used in attempts to represent ignorance. He alluded to a general key problem in frequentist statistics, that of ensuring that the long run used to calibrate coverage is relevant to the specific data sample being analysed. He also discussed in more technical detail issues of testing multiple hypotheses, including graphical methods. Cox and Reid further offered published thoughts on problems presented to them by LHC physicists. Cousins concluded that we would do well to read Cox’s contributions again.

PHYSTAT is pleased and honoured to have had the opportunity of paying its respect to a very eminent statistician and a wonderful person. His memory will long be with us.

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With her colleagues at LAPP and CERN, Marie-Noëlle created an analysis to search for Z bosons, exploiting the UA1 data extracted online by the 168E emulators – the so-called “express line”. It was by analysing these events that Marie-Noëlle spotted the first Z boson on the night of 4 May 1983 – a source of immense pleasure in her career.  

In 1987 Marie-Noëlle turned to LEP physics. She created, with Daniel Décamp, the ALEPH group at LAPP. This idea came up against obstacles: there was already an L3 group, and the rule at the time was that each IN2P3 laboratory could only participate in one experiment at LEP (with one exception). This occasion demonstrated the measure of Marie-Noëlle’s determination: when she was convinced of the merits of a project, her enthusiasm and energy were such that she was able to convince even the most reluctant. She finally obtained the green light for an ALEPH team at LAPP, which, under her direction, made many contributions to the experiment. She herself was run coordinator, responsible for calibration, and a pillar of the di-fermion analysis group (measuring the Z lineshape).  

In the early 2000s Jacques Lefrançois invited Marie-Noëlle to join the LHCb collaboration. The team at LAPP, under her direction, made a major contribution to the experiment, particularly in the construction and operation of calorimetric systems as well as in numerous physics analyses. Project manager of the calorimeter group during its start-up between 2008 and 2011, then assistant to the project manager until 2013, Marie-Noëlle participated in the commissioning and definition of control and calibration procedures for the calorimeters and ensured the continuous monitoring of the gains and of the aging of the cells of the electromagnetic calorimeter throughout the first period of data taking (2011–2013). 

Between 2000 and 2006 Marie-Noëlle was deputy director of LAPP, during which she strongly contributed to the definition and implementation of its scientific strategy. Very careful to communicate our science to the public, her creativity enabled her to organise several original and appreciated events. Marie-Noëlle supervised nine theses. For services rendered to research, she received one of the highest awards in France (de chevalier de la Légion d’honneur). 

She was certainly demanding, much more of herself than of others, but always convinced that in a group everyone makes a positive contribution. A physicist and communicator of immense talent, she was above all a woman of limitless generosity, with a sometimes caustic sense of humour. She was brave and couldn’t stand injustice, often expressing aloud what others were quietly thinking. Marie-Noëlle loved swimming, sailing, cooking, reading and welcoming her many friends and family to her table. Those who, like us, have had the chance to work with her will miss her boundless commitment, the relevance of her advice and her humanity. We are thinking of Claude, her husband of 50 years, and of her large family. 

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Gérard Bachy arrived at CERN in 1967, straight after graduating from ETH Zurich, and spent his entire 35-year career there. He started off as a mechanical engineer with the Big European Bubble Chamber, where he was in charge of the design and manufacture of the expansion system. In 1972 he joined the team of John Adams that was building CERN’s new flagship facility, the Super Proton Synchrotron (SPS), taking on responsibility for its coordination and installation. The first protons were injected into the SPS on 3 May 1976. Gérard was then approached by Giorgio Brianti, deputy head of the SPS division, to set up a section in charge of the underground-area infrastructure and installation of the experiments. He formed a motivated team where new ideas thrived and were put into practice – including a bicycle-driven system for moving detector components weighing several dozen tonnes using air cushions. 

In 1981, when the huge Large Electron–Positron (LEP) collider project was taking shape, Gérard and his team were brought in by director-in-charge Emilio Picasso. They were soon merged with the engineering group to become the LEP–IM group, which went on to play a key role in the realisation of LEP. More innovations were in store to solve the many challenges associated with this project: modular access shafts; a monorail to facilitate the installation of various components; highly precise planning, logistics and others. The project moved fast, culminating in the start-up of LEP on 14 July 1989.

The engineering for the accelerators was spread across the various CERN divisions, which hampered efficiency. In 1990, Director-General Carlo Rubbia entrusted Gérard with bringing all the different activities together under one umbrella, and the mechanical technologies division was born. Over the next five years, the focus was on modernising the facilities, infrastructures and working methods, first for the LEP200 project and then for the LHC preparations. Gérard fostered the development of the engineering and equipment data-management service, encouraged the creation of quality assurance plans and promoted a project-management culture.

In 1996, Hans Hoffmann, the technical coordinator for ATLAS, appointed Gérard as project engineer in his technical coordination and integration team. Gérard’s experience was to have a big impact on important technical choices, such as the “large wheel” concept for the ATLAS muon spectrometer. He retired in June 2001 to be able to devote more time to his other great passions, sailing and travel. 

Gérard Bachy was a brilliant engineer and a charismatic leader. He played an undisputed role at the top level of engineering at CERN and acted as a mentor for many of us.

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Experimental particle physicist Jean-Charles (Charlie) Chollet passed away on 24 August 2021. He had spent his whole scientific career at CERN, working as a member of the Orsay Laboratoire de l’Accélérateur Linéaire. His work was always in the area of precision measurements involving subtle analyses.

Charlie started at the CERN Proton Synchrotron with his thesis, defended in 1969 under the supervision of Jean-Marc Gaillard, on the observation of the interference between K_L and K_S in the π⁰π⁰ decay mode. He then contributed to the WA2 experiment at the Super Proton Synchrotron (SPS) studying leptonic decays of hyperons, where he took care of one of the most difficult components of the detector, the DISC Cherenkov counter, which led to the impressive achievement of separating ~200 GeV/c Σ^– and Ξ^– hyperons thanks to a combination of subtle optics and of a complex system of photodetection. He then participated in the UA2 experiment at the SPS pp̅ collider, where he was in charge of the pre-shower detector calibration and performance. 

Later he engaged himself in the preparation of the ATLAS experiment at the LHC, where he performed several studies, notably on the pileup background properties and their expected impact on the design of the liquid-argon calorimeter electronics. He also participated in test-beam analysis of early “accordion calorimeters”, prototypes of this same calorimeter. He ended his career at the NA48 experiment, which was measuring the direct CP violation parameter ε´/ε in neutral kaon decays and where he made an important contribution with the analysis of kaon scattering in the collimator. From small inconsistencies in the data, he managed to find and understand the source of this background, thereby allowing it to be precisely taken into account in the measurement.

He was a great sportsman, especially sailing, skiing and cycling. Those who worked with Jean-Charles Chollet will always remember the pleasure of his company, his dry sense of humour and the depth and refinement of his work, which was always presented with the utmost modesty.

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Long-time ALICE collaborator and authority in relativistic heavy-ion physics, Tom Cormier, passed away on 23 March after a brief illness. Tom was born in 1947 in Lexington, a suburb of Boston. After high school he went to MIT where he did both his undergraduate and graduate studies. He was an amazing physicist with a strong drive to explore the frontiers of relativistic nuclear physics, and a profound understanding of the field that enabled him to build the best tools to take us to those frontiers. 

After obtaining his PhD from MIT in 1974, Tom took up postdoc positions at Stony Brook and the Max Planck Institute. He then joined the University of Rochester, where he later became director of the Nuclear Structure Research Laboratory. In 1988 he moved to the Cyclotron Institute at Texas A&M University where he stayed for three years. Wayne State University was his next move, where he was chair of the physics and astronomy department. Tom joined the ORNL Physics Division in 2013, and reinvigorated the relativistic nuclear physics group and expanded ORNL’s very successful involvement in the ALICE experiment at the LHC, sPHENIX at RHIC and most recently in the Electron-Ion Collider (EIC) under construction at Brookhaven.

Tom’s work spanned an amazing breadth of physics and technology. Early on he worked on carbon–carbon inelastic scattering and scattering resonances; he then moved to experiments with recoil mass spectrometers at Brookhaven. Tom shifted his focus to relativistic heavy-ion physics with the AGS-E864 experiment at Brookhaven, followed by the STAR experiment at RHIC. He was the project manager for the construction of the STAR electromagnetic calorimeter and worked on the experiment from 1996 to 2005. 

Tom was one of the key scientists enabling the US heavy-ion community to join the LHC by proposing the large electromagnetic calorimeter EMCAL for ALICE and by forming the ALICE US collaboration. He was project manager for ALICE US, with a key responsibility for EMCAL and its later extension, the di-jet calorimeter, DCAL. Having successfully completed this project, he took on the leadership of the barrel tracker upgrade for ALICE. He was an architect of the TPC upgrade and was TPC deputy project leader from 2013. His true leadership and professionalism have been central to the success of ALICE in the past two decades. Tom most recently helped form the ECCE detector concept for the EIC. 

Both a great leader and project manager, Tom was a real inspiration, not only to his close colleagues but also to the broader community that held him in such high regard. He has been a wonderful mentor to many of us, and his contributions to the global physics programme, and to the ORNL physics division in particular, have been immense. He was an expert navigator of the various funding agencies and always showed immense calm during numerous DOE reviews, his dry sense of humour reflected in one of his memorable quips: “If I would wear a suit today, the DOE would be sure we screwed up badly.” He will be sorely missed but his legacy will remain.

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Theorist Alberto Sirlin, a pioneer in electroweak radiative corrections, passed away on 23 February aged 91. His work played a key role in confirming predictions of the Standard Model (SM) at the ±0.1% level. He was a professor at New York University for 62 years, mentored 14 PhD students and remained an active researcher until shortly before his death. 

Born in Buenos Aires in 1930, Alberto received a physics and mathematics degree from the University of Buenos Aires in 1953. That year he went to Brazil where he took a quantum mechanics course taught by Richard Feynman. In a 2015 essay “Remembering a Great Teacher”, Alberto fondly recalled that experience and the enduring friendship that followed. In 1954 he travelled to UCLA and collaborated with Ralph Behrends and Robert Finkelstein on an early study of QED radiative corrections to muon decay in Fermi’s general theory of weak interactions. Alberto then moved to graduate school at Cornell University, where he collaborated with Toichiro Kinoshita on the QED corrections to muon and nuclear beta decays in the V-A Fermi theory. Their investigation showed that QED corrections increased the muon lifetime by about 0.4% – an effect still used to define the Fermi constant. For nuclear beta decay, where QED effects were logarithmically dependent on an arbitrary cutoff scale, Alberto would later show how electroweak unification determines this scale. After Cornell he spent two years (1957–1959) as a postdoc at Columbia University, supervised by T D Lee, before joining the faculty of New York University. He also held visiting appointments at BNL, CERN, Hamburg University, Rockefeller University and The Institute for Advanced Study.

When the SM came together in the early 1970s, Alberto’s early work on QED corrections to weak-interaction processes uniquely prepared him for a leading role in computing electroweak quantum loop corrections. For example, he showed how additional loop corrections involving W and Z bosons led to a replacement of the logarithmic cutoff found in semi-leptonic beta decays by the Z-boson mass, resulting in a ~2% increase for all semi-leptonic charged-current decay rates. This is essential for unitarity tests of the quark mixing matrix, and confirms the validity of the SM at more than 20σ!

In a 1980 paper that has been cited more than 1400 times, Alberto introduced the on-shell renormalisation scheme based on physical parameters and the quantity Δr, which encodes the radiative effects. This scheme has been used to study deep-inelastic neutrino–nucleus scattering, neutrino-electron scattering, atomic parity violation, polarised electron–electron scattering asymmetries, W&Z precise mass predictions, and more, not only by Alberto and his former students and collaborators, but by the entire particle-physics community in searches for new-physics effects. Together with his former student William Marciano, he won the 2002 J J Sakurai prize of the American Physical Society for their pioneering work on radiative corrections.

In witnessing the rise and then completion of the SM with the discovery of the Higgs boson in 2012, Alberto was able to enjoy the fruits of his labour. We, his students, have been inspired by Alberto’s dedication and enthusiasm. We are grateful that we could join his journey through life and physics. He was our great teacher.

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Before becoming a highly regarded specialist in supersymmetry, she studied the identification of B mesons produced in Z decays, which made it possible to contribute to the first measurements of the B°–B° mixing parameter as well as the forward–backward asymmetry. Supersymmetry and the search for the neutralino set Sylvie on the quest for dark matter, to which she subsequently dedicated her entire career. In 2000 she joined the Alpha Magnetic Spectrometer (AMS) collaboration – a particle-physics detector installed on the International Space Station to identify and measure fluxes of cosmic rays. She took over responsibility for the readout electronics of the electromagnetic calorimeter, introducing independent rapid triggering based solely on calorimetry. Resistance to radiation, extended temperature range, low power consumption and operation in vacuum were all technical challenges that were met thanks to Sylvie’s scientific rigour and exceptional human qualities. She had an enthusiasm and leadership that motivated and led to the success of everyone in her team. More than 15 years after its completion in 2005 and more than 10 years after its first signal on 19 May 2011, the calorimeter’s electronics are still smoothly providing data. With AMS, she searched for dark matter via deformations of antiparticle fluxes, for example in the fraction of positrons detected, one of the first AMS publications 

In 2005 Sylvie created a HESS group at LAPP. The Namibia-based gamma-ray telescope had entered its second phase with the construction of the fifth telescope, the largest with a focal length of 36 m. Sylvie took up the challenge of an ambitious mechanical project to load and unload the camera – a cube 2.5 m high and weighing 2.6 tonnes – from its data-taking position 5 m from the ground to a shelter at ground level. She then explored the potential of the facility for dark-matter searches, since its size allowed the detection threshold of photons to be lowered to 50 GeV.  

Throughout her career, Sylvie maintained close ties with phenomenologists and theorists. This collaboration began at LEP within the framework of a national supersymmetry group, where she coordinated an influential working group on the Minimal Supersymmetric Standard Model. Subsequently, with theorists, she obtained a lower bound on the mass of the lightest neutralino, a candidate for dark matter, by combining astrophysical, cosmological and collider observables. She also notably contributed to the development of an extension of the still widely used micrOMEGAs code, making it possible to calculate the spectrum of positrons and antiprotons coming from the annihilation of dark-matter particles in the galaxy.  

Always positive with students, Sylvie supervised or co-supervised around 10 theses. All these elements earned her the 2017 Joliot-Curie Prize awarded by the French Physical Society. Her enthusiasm, energy and good humour are sorely missed. We are thinking of Jean-Pierre, her husband, and her sons Edouard and Arthur. 

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State-of-the-art particle accelerators and detectors cannot be bought off the shelf. They come to life in workshops staffed by teams of highly skilled engineers and technicians – such as heavy-machinist Florian Hofmann from Austria, who joined CERN in October 2019.

Florian is one of several hundred engineers and technicians employed by CERN to develop, build and test equipment, and keep it in good working order. He works in the machining and maintenance workshop of the mechanical and materials engineering (MME) group, which acts as a partner to many projects and experiments at CERN. “We tightly collaborate with all CERN colleagues and we offer our production facility and knowledge to meet their needs,” he explains. “Sometimes the engineers, the project leaders or even the scientists come to see how the parts of their work come together. It is a nice and humbling experience for me because I know they have been conceiving components for a very long time. Our doors are open and you don’t need special permission – everyone can come round!”

Before joining CERN, Florian began studying atmospheric physics at the University of Innsbruck. After two semesters, he realised that even though he liked science he preferred not to practise it, so decided to change to engineering and programming. After completing his studies and working in diverse fields such as automotive, tool making and water power plants, he joined CERN. Like many of his colleagues, his expertise and genuine curiosity for his work helps Florian to find tailor-made solutions for CERN’s challenging projects, every one of which is different, he explains. “Years ago the job used to be a traditional mechanics job, but today the cutting-edge technologies involved make this the Formula One of production.” 

Heavy metal 

Florian is currently working on aluminium joints for the vacuum tank of the kicker magnets for the Proton Synchrotron, a fundamental component on which the technicians collaborate with many other groups. The workshop is also contributing to numerous important projects such as the FRESCA2 cryostat, which is visible at the entry of the workshop, and the crab cavities for the High-Luminosity LHC upgrade. The radio-frequency quadrupole for Linac4, which now drives all proton production at CERN, was built here, as was the cryostat for the ICARUS neutrino detector now taking data at Fermilab and parts of the AMS-02 detector operating on the International Space Station. In the 1960s, the workshop was responsible for the construction of the Big European Bubble Chamber, now an exhibit in the CERN Microcosm.

Today, the cutting-edge technologies involved make this the Formula One of production

Before any heavy-machinery work begins, the machining team simulates the machining process to avoid failures or technical issues during fabrication. Although the software is highly reliable, Florian and his co-workers have to stand by to control and steer the machine, modifying commands when needed and ensuring that the activity is carried out as required. Every machine has one person in charge, the so-called technical referent, but the team receives basic training on multiple machines to allow them to jump onto a different one if necessary. The job stands out for its dynamism, Florian explains. “At the MME workshop, we perform many diverse manufacturing processes needed for accelerator technologies, not only milling and turning of the machine but also welding of exotic materials, among others. The possibilities are countless.”

Florian’s enthusiasm reflects the mindset of the MME workshop team, where everyone is aware of their contributions to the broader science goals of CERN. “This is a team sport. When you join a club you need it to have good management, and I think that here, because of our supervisors and our group responsibility, you are made to feel like everyone is pushing in the same direction.” Being curious, eager to learn and open-minded are important skills for CERN technicians, he adds.

“When you come to CERN you always leave with more than you can bring, because the experience of contributing to science, to bring nations together towards a better world, is really rewarding. I think everybody needs to ask themselves what they want and what kind of world they want to live in.”

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Theoretical physicist Claude Bouchiat, who was born in Saint-Matré (southern France) on 16 May 1932, passed away in Paris on 25 November. He was a frequent visitor to the CERN theory group. 

Bouchiat studied at the École Polytechnique in 1953–1955, and discovered theoretical high-energy physics after listening to a seminar by the late Louis Michel. In 1957, having been impressed by a conference talk given by C N Yang during a short visit to Paris, he decided to extend Michel’s results on the electron spectrum in muon decays to include the effects of parity violation. This work led to the Bouchiat–Michel formula. He then joined the theoretical physics laboratory (newly created by Maurice Lévy) at the University of Orsay where, together with Philippe Meyer, he founded a very active group in theoretical particle physics. In the 1960s, during several visits to CERN, he collaborated with Jacques Prentki. In 1974 Bouchiat and Meyer moved to Paris and established the theoretical physics laboratory at the École Normale Supérieure (ENS). 

Bouchiat’s research covered a large domain that extended beyond particle physics. With Prentki and one of us (JI) he studied the leading divergences of the weak interactions, which was a precursor to the introduction of charm, and with Daniele Amati and Jean-Loup Gervais showed how to build dual diagrams satisfying the unitarity constraints. The trio also extended the anomaly equations in the divergence of the axial current to non-abelian theories. In the early 1970s, Bouchiat and collaborators used quantum field theory in the infinite momentum frame to shed light on the parton model. In 1972, with Meyer and JI, he formulated the anomaly cancellation condition for the Standard Model, establishing the vanishing sum of electric charges for quarks and leptons as essential for the mathematical consistency of the theory.

Probably his most influential contribution, carried out with his wife Marie-Anne Bouchiat, was the precise computation of parity-violation effects resulting from virtual Z-boson exchange between electrons and nuclei. They pointed out an enhancement in heavy atoms that rendered the tiny effect amenable to observation. This work opened a new domain of experimental research, starting first at ENS, which played an important role alongside the high-energy experiments at SLAC in confirming the structure of the weak neutral current. Examples of Bouchiat’s contributions outside particle physics include his studies of the elasticity properties of DNA molecules and of the geometrical phases generated by non-trivial space topology in various atomic and solid-state physics systems. 

During his 60-year-long career, Claude Bouchiat had a profound influence on the development of French theoretical high-energy physics. He helped nurture generations of young theorists, and many of his former students are well-known physicists today. 

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Yulian Aramovich Budagov, a world-class experimental physicist and veteran JINR researcher, passed away on 30 December. Born in Moscow on 4 July 1932, he graduated from the Moscow Engineering Physics Institute in 1956 and joined the staff of the Joint Institute for Nuclear Research (JINR), to where his lifelong scientific career was connected. He made a significant contribution to the development of large experimental facilities and achieved fundamentally important results, including: the properties of top quarks; the observation of new meson decay modes; measurements of CP-violating and rare-decay branching ratios; the determination of νN scattering form factors; observation of QCD colour screening; verification of the analytical properties of πр interaction amplitudes; and observation of scaling regularities in the previously unstudied field of multiple processes.

The exceptionally wide creative range of his activities was most prominently manifested during the preparation of experiments at TeV-scale accelerators. In 1991–1993 he initiated and directly supervised the cooperation of JINR and domestic heavy-industry enterprises for the Superconducting Super Collider, and in 1994 became involved in the preparation of experiments for the Tevatron at Fermilab and for the LHC, then under construction at CERN. He led the development of a culture using laser-based metrology for precision assembly of large detectors, and the meticulous construction of the large calorimetric complex for the ATLAS experiment. Budagov also devised a system of scintillation detectors with wave-shifting fibres for heavy-quark physics at the Tevatron’s CDF experiment, which helped measure the top-quark mass with a then-record accuracy. He was a leading contributor to JINR’s participation in the physics programme for the ILC, and initiated unique work on the use of explosion welding to make cryogenic modules for the proposed collider.

In his later years, Budagov focused on the development of next-generation precision laser metrology, which has promising applications such as the stabilisation of luminosity at future colliders and the prediction of earthquakes. Precision laser inclinometers developed under his supervision allowed the time dependence of angular oscillations of Earth’s surface to be measured with unprecedented accuracy in a wide frequency range, and are protected by several patents. 

Yulian Aramovich Budagov successfully combined multifarious scientific and organisational activities with the training of researchers at JINR and in its member states. Based on the topics of research performed under his leadership, 60 dissertations were defended, 23 of which were prepared under his direct supervision. His research was published in major scientific journals of the Soviet Union, Russia, Western Europe and the US, and in proceedings of large international conferences. His works were awarded several JINR prizes, and he received medals of the highest order in Russia and beyond. 

His memory will always remain in the hearts of all those who worked alongside him. 

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Thomas K Gaisser of the University of Delaware passed away on 20 February at the age of 81, after a short illness.

Tom was born in Evansville, Indiana, and graduated from Wabash College in 1962. He won a Marshall Scholarship that took him to the University of Bristol in the UK, where he received an MSc in 1965. He then went on to study theoretical particle physics at Brown University, receiving his PhD in 1967. After postdoctoral positions at MIT and the University of Cambridge, he joined the Bartol Research Institute in 1970, where his research interests tilted toward cosmic-ray physics. 

Tom was a pioneer in gamma-ray and neutrino astronomy, and then in the emerging field of particle astrophysics. He was a master of extracting science from the indirect information collected by air-shower arrays and other particle astrophysics experiments. Early on, he studied the extensive air showers that are created when high-energy cosmic rays reach Earth. His contributions included the Gaisser–Hillas profile of longitudinal air showers and the Sybill Monte Carlo model for simulating air showers. He laid much of the groundwork for large experiments, such as Auger and IceCube, that provide high-statistics data on the high-energy particles that reach Earth, and for how that data can be used to probe fundamental questions in particle physics.

Tom’s work was also vital in interpreting data from lower-energy neutrino experiments, such as IMB and Kamioka. He provided calculations of atmospheric neutrino production that were important in establishing neutrino oscillations and, later, for searching for neutrino phenomena beyond the Standard Model.

Tom also contributed to experimental efforts. He was a key member of the Leeds–Bartol South Pole Air Shower Experiment (SPASE), which studied air showers as well as the muons these produce in the Antarctic Muon and Neutrino Detector Array (AMANDA). The combined observations were critical for calibrating AMANDA, and were important data for understanding the cosmic-ray composition. This work evolved into a leading role for Tom in the IceCube Neutrino Observatory, where he served as spokesperson between 2007 and 2011.  

In IceCube, Tom focused on the IceTop surface array. Built, like SPASE, as a calibration tool and a veto-detector, its observations contributed to cosmic-ray physics covering a wide and unique energy range, from 250 TeV to EeV. It also made the first map of the high-energy cosmic-ray anisotropy in the Southern Hemisphere. Tom took to the task of building IceTop with gusto. For several summer seasons he travelled to Antarctica, staying there for weeks at a time to work on building the surface array, which consisted of frozen Auger-style water–Cherenkov detectors. He delighted in the hard physical labour and the camaraderie of everyone engaged in the project, from bulldozer drivers to his colleagues and their students. Tom became an ambassador of Antarctic science, in large part through a blog documenting his and his team’s expeditions to the South Pole. 

Tom may be best known to physicists through his book Cosmic Rays and Particle Physics. Originally published in 1990, it was updated to a second edition in 2016, coauthored with Ralph Engel and Elisa Resconi. It sits on the shelves of researchers in the field around the globe.

Throughout his career, Tom received many scientific awards. He became a fellow of the American Physical Society in 1984 and was internationally recognised with the Humboldt Research Award, the O’Ceallaigh Medal and the Homi Bhabha Medal and Prize, among others. His Antarctic contributions were recognised when a feature on the continent was named Gaisser Valley.

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You’ve worked on ATLAS since the early days?

Yes, having trained as a high-energy physics experimentalist with a focus on detector R&D, I joined ATLAS in 1998 and began working on the liquid-argon (LAr) calorimeter. I then got involved in the LAr calorimeter upgrade programme, when we were looking at the possible replacement of the on-detector electronics. I then served as leader for the trigger and data-acquisition upgrade project, before being elected as upgrade coordinator by the ATLAS collaboration in October 2018, with a two-year mandate starting in March 2019 and a second term lasting until February 2023. Because of the new appointment to the Neutrino Platform I will step down and enter a transition mode until around October.

What are the key elements of the ATLAS upgrade?

The full Phase-II upgrade comprises seven main projects. The largest is the new inner tracker, the ITk, which will replace the entire inner detector (Pixel, SCT and TRT) with a fully silicon detector (five layers of pixels and four of strip sensors) significantly extended in the forward region to exploit the physics reach at the High-Luminosity LHC. The ITk has been the most challenging project because of its technical complexity, but also due to the pandemic. Some components, such as the silicon-strip sensors, are already in production, and we are currently steering the whole project to complete pre-production by the end of the year or early 2023. The other projects include the LAr and the scintillating-tile calorimeters, the muons, trigger and data acquisition, and the high-granularity timing detector. The Phase-II upgrades are equivalent in scope to half of the original construction, and despite the challenges ATLAS can rely on a strong and motivated community to successfully complete the ambitious programme.

What are the stand-out activities during your term?

The biggest achievement is that we were able to redefine the scope of the trigger-systems upgrade. Until the end of 2020 we were planning a system based on a level-0 hardware trigger using calorimeter and muon information, followed by an event filter where tracks were reconstructed by associative memory-based processing units (HTT). The system had been designed to be capable of evolving into a dual-hardware trigger system with a level-0 trigger able to run up to 4 MHz, and the HTT system reconfigured as a level-1 track trigger to reduce the output rate to less than 1 MHz. We reduced this to one level by removing the evolution requirements and replacing the HTT processors with commodity servers. This was a complex and difficult process that took approximately two years to reach a final decision. Let me take this opportunity to express my sincere appreciation for those colleagues who carried the development of the HTT for many years: their contribution has been essential for ATLAS, even if the system was eventually not chosen. The main challenge of the ATLAS upgrade has been and will be the completion of the ITk in the available timescale, even after the new schedule for Long Shutdown 3. 

What led you to apply for the position of Neutrino Platform leader?

Different factors, personal and professional. From a scientific point of view, I have been interested in LAr time-projection chambers (TPCs) for neutrino physics for many years, and in the challenge of scalability of the detector technology to the required sizes. Before being ATLAS upgrade coordinator, I had a small R&D programme at Brookhaven for developing LAr TPCs, and I worked for a couple years in the MicroBooNE collaboration on the electronics, which had to work at LAr temperatures. So, I have some synergetic work behind me. On a personal level, I’m obviously thrilled to formally become part of the CERN family. However, it has also been a difficult decision to move away from ATLAS, where I have spent more than 20 years collaborating with excellent colleagues and friends.  

I am still planning to be hands-on – that is the fun part

What have been the platform’s main achievements so far? 

Overall I would highlight the fact that the Neutrino Platform was put together in a very short time following the 2013 European strategy update. This was made possible by the leadership of my predecessor Marzio Nessi, a true force of nature, and the constant support of the CERN management. The refurbishment of ICARUS has been a significant technical success, as has the development and construction of the huge protoDUNE models for the two far detectors of LBNF/DUNE in the US. 

What’s the status of the protoDUNE modules?

The first protoDUNE module based on standard horizontal-drift (“single phase”) technology has been successfully completed, with series production of the anode plane assembly starting now. Lately, the CERN group has contributed significantly to the vertical-drift concept, which is the baseline technology for the second DUNE far detector. This was initially planned to adopt “dual phase” detection but has now been adapted so that the full ionisation charge is collected in liquid-argon after a long vertical drift. Recently, before I came on board, the team demonstrated the ability to drift and collect ionisation charges over a distance of 6 m, which requires the high voltage to be extremely stable and the liquid-argon to be very pure to have enough charge collected to properly reconstruct the neutrino event. There is still work to be done but we have demonstrated that the technology is already able to reach the requirements. The full single-phase DUNE detector has to be closed and cooled down in 2028, and the second based on vertical drift in 2029. For an experiment at such scale, this is non-trivial.

What else is on the agenda?

The construction of the LBNF/DUNE cryostats is a major activity. CERN has agreed to provide two cryostats, which is a large commitment. The cryostat technology has been adapted from the natural-gas industry and the R&D phase should be completed soon, while we start the process of looking for manufacturers. We are also completing a project together with European collaborators involving the upgrade of the near detector for the T2K experiment in Japan, and are supporting other neutrino experiments closer to home, such as FASER at the LHC. Another interesting project is ENUBET, which has achieved important results demonstrating superior control of neutrino fluxes for cross-section measurements. 

What are the platform’s long-term prospects?

One of the reasons I was interested in this position was to help understand and shape the long-term perspective for neutrino physics at CERN. The Neutrino Platform is a kind of tool that has a self-contained mandate. The question is whether and how it should or could continue beyond, say, 2027 and whether we will need to use the full EHN1 facility because we have other labs on-site to do smaller-scale tests for innovative detector R&D. Addressing these issues is one of my primary goals. There is also interest in Gran Sasso’s DarkSide experiment, which will use essentially the same cryostat technology as DUNE to search for dark matter. As well as taking care of the overall management and budget of the Neutrino Platform, I am still planning to be hands-on – that is the fun part.

What do you see as the biggest challenges ahead? 

For the next two years the biggest challenge is the delivery of the two cryostats, which is both technical and subject to external constraints, for instance due to the increase in the costs of materials and other factors. From the management perspective, one has to acknowledge that the previous leadership created a fantastic team. It is relatively small but very motivated and competent, so it needs to be praised and maintained. 

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What attracted you to the position of DESY director of particle physics?

DESY is one of the largest and most important particle-physics laboratories in the world. I was born and grew up in Hamburg and took my first career steps at DESY during my university studies. I received my PhD there in 1999 and returned as a scientist in 2016, so I know the lab very well. It is a great lab and department, with many opportunities and so many excellent people. I am sure it will be fun to work with all of them and to develop a strategy for the future.

What previous management roles do you think will serve you best at DESY? 

Being ATLAS deputy spokesperson from 2013 to 2017 was one of the best roles I’ve had in my career, and I benefitted hugely from the experience. I was fortunate to have an excellent spokesperson in Dave Charlton and I learned a lot from him, as well as from many others I worked with. I try to understand enough details to make educated decisions but not to micromanage. I also think motivating people, listening to them and promoting their talents is key to achieving common goals.

What are the current and upcoming experiments at DESY?

The biggest on-going experimental activities in particle physics are the ATLAS and CMS experiments. We have large groups in both, and for each we are building a tracker end-cap based on silicon-strip detectors at our detector assembly facility, primarily together with German universities. This is a huge undertaking that is currently ongoing for the HL-LHC. Another important activity is to build a vertex detector to be installed in 2023 at the Belle II experiment running at KEK in Japan. We also have a significant programme of local experiments covering axion searches. One of the big projects next summer will be the start of the ALPS II experiment, which will look for axion-like particles by shining an intense laser on a “wall” and seeing if any laser photons appear on the other side, having been transformed into axions by a large magnetic field. We have two other axion experiments planned: BabyIAXO, which looks for axion-like particles coming from the Sun, for which construction is now starting; and MadMax, which looks for axions in the dark-matter halo. Axions were postulated by Peccei and Quinn to solve the strong-CP problem but are also a good candidate for dark matter if they exist. A further experiment, which DESY theorist Andreas Ringwald and I proposed, LUXE, would deliver the European XFEL 16.5 GeV electron beam into a high-intensity laser so that the beam electrons experience a very strong electromagnetic field within their rest frame. LUXE would reach the so-called Schwinger limit, and allow us to see what happens when QED becomes strong and transitions from the perturbative to the non-perturbative regime. 

There are many accelerators at DESY, such as PETRA, where the gluon was discovered in the 1970s. Today, PETRA is one of the best synchrotron-radiation facilities in the world and is used for a wide range of science, for example imaging of small structures such as viruses. It is an application of accelerators where the impact on society is more direct and obvious than it is in particle physics. 

How can we increase the visibility of particle physics to society?

This is a very important point. The knowledge we get from particle physics today is clear, but it is less clear how we can transfer this knowledge to help solve pressing problems in society, such as climate change or a pandemic. Humankind desires to increase its knowledge, and it is important that we continue with fundamental research purely to increase our knowledge. We have already come so far in the past 5000 years. And, many technical innovations were made for that purpose alone but then resulted in transformative changes. Take the idea of the accelerator. It was developed at Berkeley during the 1930s with no particular application in mind, but today is used routinely around the world to prolong life by irradiating tumours. Or the transistor, without which there would not be any computers, which was developed in the 1920s based on the then-emerging understanding of atoms. It is important to promote both targeted research that directly addresses problems as well as fundamental research, which every now and again will result in groundbreaking changes. When thinking about our projects and experiments we need to keep in mind if and how any of our technical developments can be made in a way that addresses big societal problems.

It is important that we inspire the general public, in particular the young, about science. Educational programmes are key, such as Beamline for Schools, which is one of CERN’s flagship schemes. This was hosted by DESY during Long Shutdown 2 and a team at DESY will continue the collaboration.

CERN recently launched its Quantum Technology Initiative. Does DESY have plans in this area? 

DESY received funding from the state of Brandenburg to build a centre for quantum computing, the CTQA, which is located at DESY’s Zeuthen site. Karl Jansen, one of our scientists there, has spent most of his life working on lattice QCD calculations and is leading this effort. I myself am involved in research using quantum computing for particle tracking at the LUXE experiment. The layout of the tracker for this experiment is simpler compared to the LHC experiments, which is why we want to do it here first. We have to understand how to use quantum computers in conjunction with classical computers to solve actual problems efficiently. There is no doubt that quantum computing solves questions that are otherwise not possible, and we also think they will be able to solve problems more efficiently by using less resources compared to classical machines. That could also contribute to reducing the impact of computing on climate change.

What was your participation in the 2020 update of the European strategy for particle physics (ESPPU) and how have things progressed since? 

It was exciting to be part of the ESPPU drafting process. I was very impressed by the sincerity and devotion of the people in the hall in Bad Honnef when the process concluded. There was a lot of respect and understanding of the different views on how to balance the scientific ambitions with the realities of funding, R&D needs and other factors.

The ESPPU recommended first and foremost to complete the HL-LHC upgrade. This is a big undertaking and demands our focus. For the future, an electron-positron Higgs factory is the highest priority, in addition to ramping up accelerator R&D. Last year an accelerator R&D roadmap was prepared following the ESPPU recommendation. Very different directions are laid out, and now the task is to understand how to prioritise and streamline the different directions, and to ensure the relevant aspects are progressing significantly by the next update (probably in 2026). For instance CERN’s main focus is R&D on the next generation of magnets for a new hadron machine, while DESY has a strong progamme in plasma-wakefield accelerators for electron machines. But both DESY and CERN are also contributing to other aspects and there are other labs and universities in Europe which make important contributions. At DESY we also try to exploit synergies between developing new accelerators for photon science and high-energy physics. 

What is the best machine to follow the LHC?

The next machine needs to be a collider that can measure the Higgs properties at the per-cent and even in some cases the per-mille level – a Higgs factory. In addition to the excellent scientific potential, factors to consider are timescale and cost, but also making it a “green” accelerator and considering its innovation potential. Finding a good balance there is not easy, and there are several proposals that were studied as part of the ESPPU.

What are your three most interesting open questions in particle physics? 

Mine are related to the Higgs boson. One is the matter–antimatter asymmetry, because the exact form of the electroweak phase transition is closely related to the Higgs field. If it was a smooth transition, it cannot explain the matter–antimatter asymmetry; if it was violent, it could potentially be able to explain it. We should be able to learn something about this with the HL-LHC, but to know for sure we need a future collider. The second question is why is there a muon? Flavour physics fascinates me, and the Higgs-boson is the only particle that distinguishes between the electron, the muon and the tau, which is why I would like to study it extensively. The third question is what is dark matter? One intriguing possibility is that the Higgs boson decays to dark-matter particles, and with a Higgs factory we could measure this, even if it only happens for 0.3% of all Higgs bosons. The Higgs boson is so important for understanding our universe, that’s why we need a Higgs factory, although we will already learn a lot from the LHC and HL-LHC.

Today, women make up more than 30% of the scientists at DESY, whereas in 2005 it was less than 10%

Is the community doing a good job in communicating beyond the field? 

It is crucial that scientists communicate scientific facts, especially now when there are “post-truth” tendencies in society. We have a duty as people who are publicly funded to communicate our work to the public. Many people are excited about the origin of the universe and the fundamental laws of physics we are studying. Activities such as the CERN and DESY open days attract many visitors. We also see really good turnouts at public lectures as well as during our “science on tap” activity in Hamburg. I gave a talk about the first minutes of the universe, and the bar was packed and people had many questions during one of these events. We should all spend some of our time communicating science. Of course, we have to mostly do the actual research, otherwise we do not have anything to communicate. 

You are the first female director in DESY’s 60-year history. What do you think about the situation for women in physics, for instance the “25 by ‘25” initiative?

The 25 by ‘25 initiative is good. We have been fortunate at DESY that there was a strong drive from the German government. Research funding has increased a lot during the past 10–15 years and there was dedicated funding available to attract women to large research centres. Today, women make up more than 30% of the scientists at DESY, whereas in 2005 it was less than 10%. Having special programmes unfortunately appears to be necessary as change happens too slowly by itself otherwise. Having women in visible roles in science is important. I myself was inspired by several women in particle physics, such as Beate Naroska, the only female professor at the physics department when I was a student, Young-Kee Kim, who was spokesperson of the CDF experiment when I was a postdoc and later deputy-director of Fermilab, and last but not least Fabiola Gianotti, who was spokesperson of ATLAS when I joined and is now the Director-General of CERN. 

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Italian theoretical physicist Luciano Girardello passed away in January, aged 84. He made important contributions to quantum field theory, supersymmetry and supergravity, and will always be remembered by friends and colleagues for his irony, vision and great humanity.

Born on 10 September 1937, Luciano graduated at the University of Milano. After a first postdoctoral fellowship at Boulder, Colorado, he worked at many institutions across the world, including Harvard University, the École normale supérieure in Paris and CERN. Upon his return to Italy, he became professor at the University of Milano, where he spent several years, and in 2000 he moved to the new University of Milano-Bicocca, contributing to the creation of its physics department, where he remained for the rest of his career.

Luciano was one of the first to study the mechanisms of supersymmetry breaking, rooting the theory in reality

Luciano was interested in all aspects of fundamental physics, from quantum field theory to gravity, and made seminal contributions to the foundations of supersymmetry and supergravity in their early days. In a fruitful collaboration with other pioneers of the subjects, including Eugène Cremmer, Sergio Ferrara and Antoine Van Proeyen, he investigated the coupling of matter in supergravity, which is fundamental for the experimental search for supersymmetry, the modern theory of gravitation and the effective theories of string compactifications. Luciano was one of the first to study the mechanisms of supersymmetry breaking, rooting the theory in reality. In the final part of his career, he applied the AdS/CFT correspondence, or gauge/gravity duality, to the understanding of fundamental problems in quantum field theory. He was not interested in theoretical speculations or mathematical tricks but rather in understanding the nature of things and in the cross-fertilisation of fields and ideas. Many of his contributions to physics were born in the corridors of the CERN theory division, in long days and endless nights spent with friends and collaborators.

Luciano’s wide and original lectures on different topics at the universities of Milano and Milano-Bicocca inspired students for more than 30 years. His deep thoughts, vision and culture also informed and educated many generations of talented young physicists who are now active in the international arena. Greatly admired as a physicist, he will be remembered by those who had the good fortune to know him well as a great human being, a cultivated and refined person, and an old-time gentleman.

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Patricia McBride, distinguished scientist at Fermilab, has been elected as the next spokesperson of the CMS collaboration. She will take over from current spokesperson Luca Malgeri in the autumn, becoming the first woman to lead the 3000-strong collaboration.

McBride graduated in physics at Carnegie Mellon University, and completed a PhD at Yale analysing charm decays at Fermilab’s E630 experiment. After a postdoc at Harvard working on the Crystal Ball experiment at DESY and the L3 experiment at CERN, she joined Fermilab in 1994, later becoming head of its scientific computing programmes and head of the Particle Physics Division. Since joining CMS in 2005, she has served as deputy head of CMS Computing, head of the CMS Center at Fermilab and as US CMS Operations programme manager. She was deputy CMS spokesperson from 2018 to 2020.

It will be a challenging, but exciting time for the collaboration

Patricia McBride

Among other appointments, McBride was chair of the American Physical Society (APS) Division of Particles and Fields, the US Liaison Committee of the International Union of Pure and Applied Physics (IUPAP) and the IUPAP Commission for Particles and Fields. In 2009 she was elected as an APS fellow for her original contributions to flavour physics at LEP and the Tevatron, and for the development of major new initiatives in B physics and collider physics.

McBride’s love for particle physics started at the end of middle school when her mother gave her a book about particle accelerators. She will take up the leadership of CMS soon after LHC Run 3 gets under way, and is therefore looking forward to exciting times ahead: “CMS is looking forward to the Run-3 physics programme and at the same time will be pushing to keep the detector upgrades for the HL-LHC on track,” she says. “It will be a challenging, but exciting time for the collaboration.”

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Experimental particle physicist David Saxon passed away on 23 January. A native of Stockport, south of Manchester, where his father was a parish minister, he attended the University of Oxford and obtained his doctorate measuring pion–nucleon scattering at the Rutherford Laboratory, followed by a short postdoc there. His doctoral research took him to Paris and Berkeley, where in both cases he reported that his arrival was marked by the onset of student riots.

After a period at Columbia University, he moved to Illinois to work in Leon Ledermann’s group at the newly built Fermilab. Here he helped to develop electron and muon identification techniques, which would prove fruitful in future electroweak experiments. The group did not discover the W and Z, but did find a signal that was later associated with charm mesons. Returning to Rutherford, soon to be Rutherford Appleton Laboratory (RAL), in 1974 David was quickly promoted to senior researcher. Realising that the future lay in “counter” physics, rather than bubble chambers, he worked on hadron–proton scattering in the resonance region. With the PETRA collider at DESY announced soon afterwards, David helped to form the UK contribution to the TASSO experiment, which made important measurements of electron–positron scattering. The PETRA experiments would go on to discover the gluon, enabling the Standard Model to be constructed with confidence.

After PETRA came HERA, which remains the world’s only high-energy electron–proton collider. David first led the RAL team working on the central tracking detector for the ZEUS experiment, but it was not long before he was invited to the newly reinstituted Kelvin professorship at the University of Glasgow, where he arrived in 1990 and spent the remainder of his academic career. He built the group significantly, its present healthy state founded on what he achieved. In addition to taking Glasgow into ZEUS, he nurtured many other activities – in particular involvement in the ALEPH experiment at LEP – and was instrumental in the design of central tracking systems for projects that eventually combined to become ATLAS.

David was instrumental in the design of central tracking systems for projects that eventually combined to become ATLAS

He was hardly installed in Glasgow before being appointed for several years as chair to the UK’s former Particle Physics Committee. There was no more important position to hold at the time, and David’s good sense, insight and intelligence helped to enable the subject to survive and prosper during a time when funding was tight and the UK funding system was being reorganised. Undaunted, he convinced the group in Glasgow that now was an excellent opportunity to host the 1994 edition of ICHEP.

David was one of the most sociable of people, always a good team player and invariably provocative and stimulating in conversation. Inevitably, the call came to move higher up in the university, first as a highly regarded head of department and later as dean of the science faculty – a post he occupied until shortly before his retirement. Meanwhile, he served on numerous local, national and international committees, including the UK CERN delegation and CERN policy committees, where his perceptiveness was always in demand. The UK recognised his distinguished and important contributions to science with the award of an OBE.

It was a sadness that his final years were marked by Parkinson’s disease, but he still participated in CERN Council meetings. He was at all times supported by his wife Margaret, with whom he had a son and a daughter, and found strength and comfort in his church membership. Those who were fortunate enough to know and work with David will never forget his positive and energetic character, always fair-minded, competitive without being aggressive, and caring. He will be much missed, and inspirational memories will remain.

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Renowned Cypriot–French theoretical physicist Costas Kounnas passed away suddenly on 21 January, two days before his 70th birthday. Born in Famagusta, Cyprus, Costas did his undergraduate studies at the National and Kapodistrian University of Athens before moving to Paris for his advanced degree. His studies were interrupted by military service during the events in Cyprus in 1974, after which he completed his PhD at the École polytechnique, carrying out important calculations of QCD effects in deep inelastic scattering and jets. He joined the CNRS in 1980, and later took up a postdoctoral fellowship at CERN, where he made seminal contributions to models of supersymmetry and supergravity. In particular, he helped develop supergravity models in which supersymmetry was broken spontaneously without generating any vacuum energy – a bugbear of globally supersymmetric theories. Working with Costas on these models was one of our most exhilarating collaborations.

Costas then moved to Berkeley where he became a world expert in the construction of string models, showing in particular how they could be formulated directly in four dimensions, without invoking the compactification of extra dimensions. In 1987 he took up a position at the École normale supérieure in Paris, where he remained for the rest of his career, apart from a CERN staff position between 1993 and 1998. Many of his best-known papers during these periods concerned cosmological aspects of string models, loop corrections and the breaking of supersymmetry – topics in which he was a world leader. He was also director of the theoretical physics group at the École normale supérieure between 2009 and 2013.

Costas showed how string models could be formulated directly in four dimensions

Among his accolades, Costas was awarded the Paul Langevin Prize of the French Physical Society in 1995 and the Gay-Lussac Humboldt Prize in 2013 for outstanding scientific contributions, especially to cooperation between Germany and France. In addition, he received a prestigious Research Award from the Adolf von Humboldt Foundation in 2014.

His many friends mourn the passing, not just of a distinguished theoretical physicist, but also of a warm colleague with a great heart that he was not shy of wearing on his sleeve. Costas enjoyed participating exuberantly in scientific discussions, always with the overriding aim of uncovering the truth. We remember a joyful and energetic friend who was passionate about many other aspects of life beyond science, including his many friendships and his home island of Cyprus. He was active in efforts to develop its relations with CERN, where it is now an Associate Member on its way towards full membership.

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Ronald Shellard began his journey in physics in the 1970s at the University of São Paulo, where he took his undergraduate degree, and at the Institute of Theoretical Physics of São Paulo State University, where he completed his master’s in 1973. He received his doctorate, titled “Particle physics field theory, dynamical symmetry breakdown at the two loop and beyond”, from the University of California, Los Angeles in 1978 after also spending time at the University of California, Santa Barbara.

After a period working in theoretical particle physics, Shellard devoted himself to experimental and astroparticle physics. He joined the DELPHI collaboration at the former LEP collider at CERN in 1989, and in 1995 he joined the Pierre Auger Observatory, where he made an outstanding contribution both as a researcher and as an articulator of Brazilian collaboration. Remaining in the astroparticle field, during the past decade he was also involved in the Cherenkov Telescope Array, the Large Array Telescope for Tracking Energetic Sources and the Southern Wide Field Gamma-Ray Observatory.

Shellard played a key role in efforts to make Brazil an official member of CERN

From 2009 to 2013, Shellard was vice president of the Brazilian Physical Society. He participated tirelessly on various initiatives to promote Brazilian physics, such as the establishment of the exchange programme with the American Physical Society, the strengthening of the Brazilian physics Olympiad, the in-depth study of physics and national development, the establishment of the internship programme of high-school teachers at CERN, and the initiative to create a professional master’s degree in physics teaching. He was a member of the Brazilian Academy of Science since 2017, director of the Centro Brasileiro de Pesquisas Físicas since 2015 and president of the Brazilian network of high-energy physics since 2019. He played a key role in efforts to make Brazil an official member of CERN – a process that appears to be reaching a successful conclusion, with the CERN Council voting in September 2021 to grant to Brazil the status of Associate Member State, pending the signature of the corresponding agreement and its ratification by Brazilian authorities. Active until a few days before he passed away on 7 December, Ron was very excited about this news and was making plans for the next steps of the accession procedure.

Ron Shellard had an innovative and sensibly optimistic spirit, with a comprehensive and progressive vision of the crucial role of physics, and science in general, for the progress of Brazilian society. He exerted a great influence on the formation of the research community in high-energy physics. He was the advisor of several graduate students and had a permanent commitment to the training of new scientists and the dissemination and popularisation of science in the country.

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Bernhard Spaan, an exceptional particle physicist and a wonderful colleague, unexpectedly passed away on 9 December, much too early at the age of 61.

Bernhard studied physics at the University of Dortmund, obtaining his diploma thesis in 1985 working on the ARGUS experiment at DESY’s electron–positron collider DORIS. Together with CLEO at Cornell, ARGUS was the first experiment dedicated to heavy-flavour physics, which became the central theme of Bernhard’s research work for the following 36 years. Progressing from ARGUS and CLEO to the higher-statistics experiments BaBar and ultimately LHCb, for which he made early contributions, he was one of the pioneering leaders in the next generation of heavy-flavour experiments at both electron–positron and hadron colliders.

While working on tau–lepton decays at ARGUS for his doctorate, Bernhard led a study of tau decays to five charged pions and a tau neutrino, which resulted in the world’s best upper limit for the tau-neutrino mass at the time. He also pioneered a new method of reconstructing the pseudo mass of the tau lepton by approximating the tau direction with the direction of the hadronic system. This method led to a new tau-lepton mass, which was an important ingredient to resolve the long-standing deviation from lepton universality as derived from the measurements of the tau lifetime, mass and leptonic branching fraction.

In 1993 Bernhard joined McGill University in Montreal, where he contributed to CLEO operation, data-taking and analysis, and was brought into contact with the formative stages of an asymmetric electron–positron B-factory at SLAC. He was an author of the BaBar letter of intent in 1994 and remained a leading member of the collaboration for the two following decades.

Bernhard saw the unique potential of a dedicated B experiment at the LHC and joined the LHCb collaboration

In 1996 Bernhard started a professorship at Dresden where, together with Klaus Schubert, he built a strong German BaBar participation including involvement in the construction and operation of the calorimeter. At that time, BaBar was pioneering the use of distributed computing resources for data-processing. As one of the proponents of this approach, Bernhard played a crucial role in the German contribution via the computing centre at Karlsruhe, later “GridKa”. Building on the success of the electron–positron B-factories, Bernhard saw the unique potential of a dedicated B experiment at the LHC and joined the LHCb collaboration in 1998.

Bernhard’s scientific journey came full circle when he accepted a professorship at Dortmund University in 2004, which he used to significantly grow his LHCb participation. The Dortmund group is one of LHCb’s largest, with a long list of graduate students and main research topics including the determination of the CKM angles β and γ governing CP violation in rare B decays. In parallel with LHC Run 1 and 2 data-taking, Bernhard investigated the possibility of using scintillating fibres for a novel tracking detector capable of operating at much larger luminosities. In all phases of the “SciFi” detector, which was recently installed ahead of LHC Run 3, he supported the project with his ideas, his energy and the commitment of his group.

Bernhard was an outstanding experimental physicist whose many contributions shaped the field of experimental heavy-flavour physics. He was also a great communicator. His ability to resolve conflicts and to find compromises brought many additional tasks to Bernhard, whether as dean of the Dortmund faculty, chair of the national committee for particle physics, member of R-ECFA or chair of the LHCb collaboration board. When help was needed, Bernhard never said “no”.

We have lost a tremendous colleague and a dear friend who will be sorely missed not only by us, but the wider field.

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In the gold-medal category David Deutsch of the University of Oxford has been awarded the Isaac Newton Prize “for founding the discipline named quantum computation and establishing quantum computation’s fundamental idea, now known as the ‘qubit’ or quantum bit.” In the same category, Ian Chapman received the Richard Glazebrook Prize “for outstanding leadership of the UK Atomic Energy Authority and the world’s foremost fusion research and technology facility, the Joint European Torus, and the progress it has delivered in plasma physics, deuterium-tritium experiments, robotics, and new materials”.

Among this year’s silver-medal recipients, experimentalist Mark Lancaster of the University of Manchester earned the James Chadwick Prize “for distinguished, precise measurements in particle physics, particularly of the W boson mass and the muon’s anomalous magnetic moment”. Michael Bentley (University of York) received  the Ernest Rutherford Prize for his contributions to the understanding of fundamental symmetries in atomic nuclei, while Jerome Gauntlett (Imperial College London) received the John William Strutt Lord Rayleigh Prize for applications of string theory to quantum field theory, black holes, condensed matter physics and geometry.

Finally, in the bronze medal category for early-career researchers, the Daphne Jackson Prize for exceptional contributions to physics education goes to accelerator physicist Chris Edmons (University of Liverpool) in recognition of his work in improving access for the visually impaired, for example via the Tactile Collider project. And the Mary Somerville Prize for exceptional contributions to public engagement in physics goes to XinRan Liu (University of Edinburgh) for his promotion of UK research and innovation to both national and international audiences.

Acknowledging physicists who have contributed to the field generally, 2021 honorary Institute of Physics fellowships were granted to Lyn Evans (for sustained and distinguished contributions to, and leadership in, the design, construction and operation of particle accelerator systems, and in particular the LHC) and climate physicist Tim Palmer, a proponent of building a ‘CERN for climate change’, for his pioneering work exploring the nonlinear dynamics and predictability of the climate system.

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Experimental particle physicist Beate Heinemann has been announced as the new director of DESY’s High Energy Physics division, effective from 1 February. Succeeding interim director Ties Behnke, who held the position since January 2021 when Joachim Mnich joined CERN as director for research and computing, she is the first female director in DESY’s 60-year history.

After completing a PhD at the University of Hamburg in 1999, based on data from the H1 experiment at DESY’s former electron-proton collider HERA, Heinemann did a postdoc at the University of Liverpool, UK, working on the CDF experiment at Fermilab.  She became a lecturer at Liverpool in 2003, a professor at UC Berkeley in 2006 and a scientist at Lawrence Berkeley National Laboratory.

In 2007 Heinemann joined the ATLAS collaboration in which she helped with the installation, commissioning and data-quality assessment of the pixel detector as well as performing other roles including as data-preparation coordinator during the LHC startup phase. She was deputy spokesperson of the ATLAS collaboration from 2013 to 2017, and since 2016 has been a senior scientist at DESY and W3 professor at Albert-Ludwigs-Universität Freiburg. She was also a member of the Physics Preparatory Group during the 2020 update of the European strategy for particle physics, and since 2017 she has been a member of the CERN Scientific Policy Committee.

Born in Hamburg, Heinemann is looking forward to the many exciting challenges, both scientifically and socially, ahead: “It is very important that we retain and further expand our pioneering role as a centre for fundamental research for the study of matter. In the next few years, the course will be set for the successor project to the LHC, whose technology and location have not yet been chosen. DESY must be actively involved in the preparation of this project in order to maintain and expand its pioneering role,” she explains. “Another topic that is very close to my heart, both personally and through my new office, is diversity. DESY should remain a cosmopolitan, diverse laboratory, and there is still room for improvement in many areas, for example the number of women in management positions.”

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On 15 November, around 260 physicists gathered at CERN (90 in person) to participate in the 2021 LHC Career Networking event, which is aimed at physicists, engineers and others who are considering leaving academia for a career in industry, non-governmental organisations and government. It was the fifth event in a series that was initially limited to attendance only by members of LHC experiments but which, in light of its strong resonance within the community, is now open to all.

Former members of the LHC experiments were invited to share their experiences of working in fields ranging from project management at the Ellen MacArthur Foundation, to consultants like McKinsey and pharmaceutical companies such as Boehringer Ingelheim. They spoke movingly of the difficulties of leaving academia and research, the introspection they experienced to discover the path that was right for them, and the sense of satisfaction and happiness they felt in their new roles.

Adjusting to new environments

Following a supportive welcome from Joachim Mnich, CERN director of research and computing, and Marianna Mazzilli, a member of the ALICE collaboration and chair of the organising committee, the first speaker to take to the stage in the main auditorium was Florian Kruse. Florian was a physicist on the LHCb experiment who, upon leaving CERN, decided to set up his own data-science and AI company called Point 8 – a throwback from many years spent commuting to the LHCb pit at LHC Point 8. His company has grown from three to 20 staff members, some ex-CERN, and continues to expand.

Setting the tone for the evening, he talked about what to expect when interacting with industry, how people view CERN physicists and where and how adjustments have to be made to adapt to a new environment – advising participants to “recalibrate your imposter syndrome” and “adjust to other audiences”.

Julia Hunt, a former CMS experimentalist, shared a personal insight into her journey out of academia, revealing that she fortuitously came across sailor Ellen MacArthur’s TED talk and soon landed the job of project manager at the Ellen MacArthur Foundation.

The field of data science has welcomed numerous former CERN physicists, among them ex-ATLAS members Max Baak and Till Eifert, former CMS and ALICE member Torsten Dahms, ex-CMS member Iasonas Topsis-Giotis and ex-ALICE member Elena Bruna. Max gave a mini-course in bond trading at ING bank, while Iasonas put a positive spin on his long search for a job by saying that each interview or application taught him essential lessons for the next application, eventually landing him a job as a manager at professional services company Ernst & Young in Belgium. In a talk titled “19 years in physics… and then?”, Torsten shared the sleepless nights he endured when deliberating whether to continue in a field that had him relocate himself and his family five times in 15 years, ultimately turning down a tenure-track position in 2019.

Elena, who despite having a permanent position left the field in 2018 to become a data scientist at Boehringer Ingelheim, highlighted the differences between physics (where data structures are usually designed in advance and data are largely available) and data science (where the value of data is not always known a priori, and tends to be more messy), and indicated areas to highlight on a data-science CV. These include keeping it to a maximum of two pages and emphasising skills and tools, including big-data analysis, machine-learning techniques, Monte Carlo simulations and working in international teams. The topic of CVs came up repeatedly, a key message being that physicists must modify the language used in academic applications because people “outside” just don’t understand our terminology.

Two networking breaks, held in person and accompanied by beer, wine and pizza for those who were present and via Zoom breakout rooms for remote participants, were alive with questions and discussion.  Former ATLAS member Till Eifert was surrounded by physicists eager to learn more about his role as a specialist consultant with McKinsey in Geneva, speaking passionately about the renewable energy, cancer diagnostics and decarbonisation projects he has worked on. Head of CERN Alumni relations Rachel Bray and her team were on hand to answer a multitude of questions about the CERN Alumni programme.

70-85% of jobs come through networking

Anthony Nardini

Emphasising the power of such events, speaker Anthony Nardini from entrepreneurial company On Deck cited a 2017 Payscale survey which found that 70–85% of jobs come through networking. Following up from the event on Twitter, he offered takeaways for all career “pivoters”: craft and prioritise your guiding principles, such as industry, job function, company stage mission; create a daily information-gathering practice so that you are reading the same newsletters, articles and Twitter feeds as those in your target roles; identify and contact “pathblazers” in your target organisations who understand your background; and do the work to pitch how your unique skillset can help a startup to grow.

All the speakers gave their time and contact details for follow-up questions and advice. The overall message was that, while the transition out of academia can be hard, CERN’s brand recognition in certain fields helps enormously. Use your connections and have confidence!

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Graham Ross, a distinguished Scottish theorist who worked mainly on fundamental particle physics and its importance for the evolution of the universe, passed away suddenly on 31 October 2021. 

Born in Aberdeen in 1944, Graham studied physics at the University of Aberdeen, where he met his future wife Ruth. In 1966 he moved to Durham University where he worked with Alan Martin on traditional aspects of the strong interactions for his PhD. His first postdoctoral position began in 1969 at Rutherford Appleton Laboratory (RAL). It was around the time that interest in gauge theories began to flourish, for which he and Alex Love were among the first to investigate the phenomenology. He continued working on this theme after he moved to CERN in 1974 for a two-year fellowship. Among the papers he wrote there was one in 1976 with John Ellis and Mary Gaillard suggesting how to discover the gluon in three-jet events due to “gluestrahlung” in electron–positron annihilation. This proposal formed the basis of the experimental discovery of the gluon a few years later at DESY.

After CERN, Graham worked for two years at Caltech, where he participated in a proof of the factorisation theorem that underlies the application of perturbative QCD to hard-scattering processes at the LHC. He then returned to the UK, to a consultancy at RAL held jointly with a post at the University of Oxford, where he was appointed lecturer in 1984. Here he applied his expertise on QCD in collaborations with Frank Close, Dick Roberts and also Bob Jaffe, showing how the evolution of valence quark distributions in heavy nuclei are in effect rescaled relative to what is observed in hydrogen and deuterium. This work hinted at an enhanced freedom of partons in dense nuclei. 

In 1992 Graham became a professor at Oxford, where he remained for the rest of his career as a pillar of the theoretical particle-physics group, working on several deep questions and mentoring younger theorists. Among the many fundamental problems he worked on was the hierarchical ratio between the electroweak scale and the Planck or grand-unification scale, suggesting together with Luis Ibañez that it might arise from radiative corrections in a supersymmetric theory. The pair also pioneered the calculation of the electroweak mixing angle in a supersymmetric grand unified theory, obtaining a result in excellent agreement with subsequent measurements at LEP. Graham wrote extensively on the hierarchy of masses of different matter particles, and the mixing pattern of their weak interactions, with Pierre Ramond in particular, and pioneered phenomenological string models of particles and their interactions. In recent years, Graham worked on models of inflation with Chris Hill, his Oxford colleagues and others.

Among his formal recognitions were his election as fellow of the Royal Society in 1991 and his award of the UK Institute of Physics Dirac Medal in 2012. The citation is an apt summary of Graham’s talents: “for theoretical work developing both the Standard Model of fundamental particles and forces, and theories beyond the Standard Model, that have led to new insights into the origins and nature of the universe”.

Graham had a remarkable ability to think outside the box, and to analyse new ideas critically and systematically. His work was characterised by a combination of deep thought, originality and careful analysis. He was never interested in theoretical speculation or mathematical developments for their own sakes, but as means towards the ultimate end of understanding nature.

Many theoretical physicists are competitive and pursue their ambitions aggressively. But this was not Graham’s way. Pursuing his ambitions with persistence and good humour, he was greatly admired as a talented physicist but also universally liked and admired, particularly by the many younger physicists whom he mentored at Oxford. He was a great teacher and an inspiration, not just to his formal students but also his daughters, Gilly and Emma, and latterly his grandchildren, James, Charlie and Wilfie.

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Gennady Zinovjev, a prominent theorist in the field of quantum chromodynamics (QCD) and the physics of strongly-interacting matter, a pioneer in experimental studies of relativistic heavy-ion collisions and a leader of the Ukraine–CERN collaboration, passed away on 19 October 2021 at the age of 80. In a career spanning more than 50 years, Genna, as he was known to most of his friends, made important theor­etical contributions to many different topics, ranging from analytical and perturbative QCD to phenomenology, and from hard probes and photons to hadrons and particle chemistry. His scientific activities were concentrated around experimental facilities at CERN and the Joint Institute for Nuclear Research (JINR), Dubna. He was one of the key initiators of the NICA complex at JINR, played a pivotal role in Ukraine becoming an Associate Member State of CERN in 2016 and was one of the founding members of the ALICE collaboration.

Born in 1941 in Birobidzhan (Russian Far East), in 1963, Zinovjev graduated from Dnepropetrovsk State University, a branch of Moscow State University. From 1964 to 1967 he studied at the graduate school of the Laboratory of Theoretical Physics of JINR, after which he spent a year at the Institute of Mathematics and Computer Science of the Academy of Sciences of the Moldavian SSR (Kishinev now Chisinau). He was awarded a PhD in physics and mathematics in 1975 at the Dubna Laboratory of Theoretical Physics and then joined the Kiev Institute for Theoretical Physics (both now the Bogolyubov Institute for Theoretical Physics) of the National Academy of Sciences of Ukraine, firstly as a staff member and then, from 1986, as head of the department of high-energy-density physics. In 2006 he was awarded the Certificate of Honour of the Verkhovna Rada (Parliament) of Ukraine, and in 2008 was awarded the Davydov Prize of the National Academy of Sciences of Ukraine becoming a member of the Academy in 2012.

In the mid-1990s Zinovjev initiated Ukraine’s participation in ALICE, and soon started to play a key role in the conception and construction of the Inner Tracking System (ITS), and more generally in the creation of both the ALICE experiment and the collaboration. Overcoming innumerable practical and bureaucratic obstacles, he identified technical and technological expertise within the Ukrainian academic and research environment, and then managed and led the development and fabrication of novel ultra-lightweight electrical substrates for vertex and tracking detectors. These developments, which took place at the Kharkiv Scientific Research Technological Institute of Instrument Engineering, resulted in technologies and components that formed the backbone of the ITS 1 and ITS 2 detectors. He was the deputy chair of the ALICE collaboration board from 2011 to 2013 and also served as a member of the ALICE management board during that time.

Genna was one of those rare people who are equally comfortable with theory, experiment, science, politics and human interactions. He was a passionate scientist, deeply committed to the Ukrainian scientific community. He did not hesitate to make great personal sacrifices to pursue what he considered important for science, his students and colleagues. Equally influential was his prominent role as a teacher and mentor for a steady stream of talent, both experimentalists and theorists. Many of us in the heavy-ion physics community owe him a great deal. We will always remember him for his charismatic personality, great kindness, openness and generosity. 

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On 5 October, Syukuro Manabe (Princeton), Klaus Hasselmann (MPI for Meteorology) and Giorgio Parisi (Sapienza University of Rome) were announced as the winners of the 2021 Nobel Prize in Physics for their groundbreaking contributions to the understanding of complex physical systems, which provided rigorous scientific foundations to our understanding of Earth’s climate. Sharing half the 10 million Swedish kronor award, Manabe and Hasselmann were recognised “for the physical modelling of Earth’s climate, quantifying variability and reliably predicting global warming”. Parisi, who started out in high-energy physics, received the other half of the award “for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales”.

In the early 1960s, Manabe developed a radiative-convective model of the atmosphere and explored the role of greenhouse gases in maintaining and changing the atmosphere’s thermal structure. It was the beginning of a decades-long research programme on global warming that he undertook in collaboration with the Geophysical Fluid Dynamics Laboratory, NOAA. Hasselmann, who was founding director of the Max Planck Institute for Meteorology in Hamburg from 1975 to 1999, developed techniques that helped establish the link between anthropogenic CO₂ emissions and rising global temperatures. He published a series of papers in the 1960s on non-linear interactions in ocean waves, in which he adapted Feynman-diagram formalism to classical random-wave fields.

Parisi, a founder of the study of complex systems, enabled the understanding and description of many different and apparently entirely random materials and phenomena in physics, biology and beyond, including the flocking of birds. Early in his career, he also made fundamental contributions to particle physics, the most well-known being the derivation, together with the late Guido Altarelli and others, of the “DGLAP” QCD evolution equations for parton densities. “My mentor Nicola Cabibbo was usually saying that we should work on a problem only if working on the problem is fun,” said Parisi following the announcement. “So I tried to work on something that was interesting and which I believed that had some capacity to add something.”

As per last year, the traditional December award ceremony will take place online due to COVID-19 restrictions. 

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Helmut Weber, CERN director of administration from 1992 to 1994, passed away on 16 July. Born in 1947, he obtained his PhD from the Technical University of Vienna, after which he pursued a steep career in the aerospace industry, where he acquired considerable managerial proficiency. Prior to joining CERN, Helmut had been chairman of the board of directors of Skyline Products (US), and member of the board of directors of the ERC (France).

Helmut played a significant role during CERN’s transition from the LEP era to the LHC project. During his three-year appointment, as successor to Georges Vianès and predecessor to Maurice Robin, he was able to implement many necessary improvements to the CERN administration. Examples include the reorganisation of the finance division (split into procurement and accounting divisions) and the creation of a CERNwide working group to standardise administrative procedures using a common online database. He also resolved a number of looming issues carried forward from the LEP era, such as the debt to the CERN Pension Fund and the financial claims made by the Euro–LEP consortium.

Furthermore, together with Meinhard Regler and the active support of CERN (including Kurt Hübner and Philip Bryant), Helmut promoted AUSTRON, a project proposal for a pulsed high-flux neutron spallation source as an international research centre for central Europe. Although this project could unfortunately not be realised due to lack of funding, the MedAustron facility for proton/ion therapy and research was eventually built as an alternative in Wiener Neustadt. It is now fully operational, serving as a successful example of technology transfer from elementary particle physics to medical applications.

Helmut Weber’s most important legacy is, however, his straightforward, uncompromising and honest character that helped to resolve many contentious internal issues at CERN. When he left the organisation, he had made many friends amongst his former colleagues, who will always remember him and miss him.

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Norwegian experimental particle physicist Egil Sigurd Lillestøl passed away in Valence, France, on 27 September. He will be remembered as a passionate colleague with exceptional communication and teaching skills, and a friend with many personal interests. He was able to explain the most complex systems and mechanisms in physics so that even the layperson felt they understood it.

Egil Lillestøl obtained his PhD from the University of Bergen in 1970. By which time he had already spent three years (1964–1967) as a fellow at CERN. He was appointed associate professor at his alma mater the same year, and then left for Paris in 1973 where he was a guest researcher at Collège de France. In 1984 Lillestøl was appointed full professor in experimental particle physics in Bergen, where he became central in the PLUTO collaboration at DESY, DELPHI and then ATLAS at CERN.

Over time, CERN became Lillestøl’s main laboratory, first as a paid associate, later as a guest professor and eventually as a staff member, contributing to the management of the experimental programme and significantly improving the conditions for the visiting scientists at the laboratory.

In Norway he acted as national coordinator of CERN activities in preparation for the LHC. He was instrumental in the organisation of the community and discussions of future funding models at the national level, in particular to accommodate the long-term commitments needed for the ATLAS and ALICE construction projects.

Egil Lillestøl played a pivotal role in the CERN Schools of Physics from 1992 until 2009, relaunching the European School of High-Energy Physics as annual events organised in collaboration with JINR, and establishing a new biennial series of schools in Latin America from 2001. He worked tirelessly on preparations for each event, in collaboration with local organisers in each host country, as well as on-site during the two-week-long events.

The Latin-American schools were an important element in increasing the involvement of scientists and institutes from the region in the CERN experimental programme, for which he deserves much credit. Beyond his official duties, he took great pleasure in interacting with the participants of the schools during their free time, and in the evenings he could often be found playing piano to accompany their singing.

As a founding member of the International Thorium Energy Committee, Lillestøl was a strong proponent for thorium-based nuclear power. He was also one of the main drivers behind the UNESCO-supported travelling exhibition “Science bringing nations together”, organised jointly by JINR and CERN.

As a teacher and a lecturer, Lillestøl was a role model. He always tailored his presentations to match the audience. His tabletop book The Search for Infinity, co-authored with Gordon Fraser and Inge Sellevåg, became a bestseller and has been published in nine language editions.

Egil Lillestøl was a bon viveur who spread joy around him. He had an impressive repertoire of anecdotes, including topics such as how to cold-smoke salmon. He enjoyed sports and was active in the CERN clubs for cycling, skiing and sailing. He leaves behind his wife and former colleague, Danielle, and two adult children from his first marriage.

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Simon Eidelman, a leading researcher at the Budker Institute of Nuclear Physics in Novosibirsk, Russia, and a professor of Novosibirsk State University (NSU), passed away on 28 June.

He was a key member of experimental collaborations at Novosibirsk, CERN and KEK, and a leading author in the Particle Data Group. Eidelman served the high-energy physics community in a variety of ways, including as Novosibirsk’s correspondent for this magazine for more than 20 years.

Simon (Semyon) Eidelman was born in Odessa in 1948. He went to Novosibirsk aged 15 to participate in a national mathematics Olympiad, and ended up staying to attend a special high school for extraordinarily gifted students. He then studied physics at NSU. Even before graduating, in 1968 Simon joined the Budker Institute and remained there his entire professional life. In parallel, he was a faculty member at NSU and held the high-energy physics chair for 10 years. Simon always cared for, helped and supported students and young colleagues.

Meson expert

Eidelman’s scientific activity mostly concerned experiments at e⁺e^– colliders, beginning with participation in the discovery of multi-hadron events at the pioneering VEPP-2 collider.

In 1974 he moved to experiments with the OLYA detector at the upgraded VEPP-2M, where a comprehensive study of e⁺e^– annihilation into hadrons was performed up to an energy of 1.4 GeV. Later, this detector was moved to the VEPP-4 collider, where high-precision measurements of the J/ψ and ψʹ masses were performed. Simon’s work at VEPP-2 and VEPP-4, and the analysis of the so-called box anomaly, made him one of the world’s leading experts on vector mesons. Together with Lery Kurdadze and Arkady Vainshtein, he also performed the first comparison of QCD sum rules with experiment.

Simon became one of the pioneers in the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon

Simon was a key member of several major experimental collaborations: KEDR, CMD-2 and CMD-3 at Novosibirsk, LHCb at CERN and Belle, Belle II and g-2/EDM at J-PARC. Recently he contributed to the KLF proposal at JLab to build a secondary beam of neutral kaons to be used with the GlueX setup for strange-hadron spectroscopy. Just last year he proposed to measure the charged kaon mass with unprecedented precision using the Siddharta X-ray experiment at DAΦNE in Frascati – which would have yielded a dramatic improvement on determinations of the masses of charmonium-like exotic mesons.

Thanks to his deep understanding of hadron-production cross sections, Simon became one of the pioneers in the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon, g-2. He was a founding member of the Muon g-2 Theory Initiative and a key contributor to its first white paper, published last year, which provides the community consensus for the Standard Model prediction. He was also an authority on strongly interacting hadrons and resonances, as well as the τ lepton and two-photon physics.

Simon was a key author in the international Particle Data Group (PDG) for 30 years, leading the PDG subgroup responsible for meson resonances since 2006. In recognition of his contributions, he was chosen to be the first author of the 2004 edition of the Review of Particle Physics. He was also a great source of inspiration for the Quarkonium Working Group (QWG). Attendees of the QWG workshops will remember his lucid presentations, his great enthusiasm for research and his keen scientific insights. Moreover, he was greatly appreciated for his wisdom and calm counsel during intense discussions.

Superb editor

Thanks to his deep knowledge and wide scientific horizons, combined with a wonderful sense of humour and a kind and friendly nature, Simon possessed a unique ability to galvanise colleagues into joint projects within many international collaborations and meetings. He was also deeply engaged in training the next generations of physicists, most recently being the driving force behind the school on muon g-2.

Simon was also a superb scientific editor. He had a rare gift of formulating scientific problems and results clearly and concisely, providing an invaluable contribution to the very large number of papers that he authored, co-authored and refereed. Several international meetings have been dedicated to Simon’s memory, including CHARM 2021 and the 4th Plenary Workshop of the Theory Initiative.

We have lost a remarkable physicist, and a dear and kind person. All who had the privilege of knowing and working with Simon Eidelman will always remember him as an invaluable colleague.

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On 23 July, the great US theoretical physicist Steve Weinberg passed away in hospital in Austin, Texas, aged 88. He was a towering figure in the field, and made numerous seminal contributions to particle physics and cosmology that are part of the backbone of our current understanding of the fundamental laws of nature. He is part of the reduced rank of scientists who, in the course of history, have radically changed the way we understand the universe and our place in it.

Weinberg was born in New York, the son of Jewish immigrants, Eve and Frederick Weinberg. He attended the Bronx High School of Science, where he met Sheldon Glashow, later to become his Harvard colleague and with whom he would share the 1979 Nobel Prize in Physics. Towards the end of high school, Weinberg was already set on becoming a theoretical physicist. He obtained his undergraduate degree at Cornell University in 1954, and then spent a year doing graduate work at the Niels Bohr Institute in Copenhagen, after which he returned to the US to complete his graduate studies at Princeton. His PhD advisor was Sam Treiman and his thesis topic was the application of renormalisation theory to the effects of strong interactions in weak processes. Weinberg obtained his degree in 1957 and then spent two years at Columbia University. From 1959 to 1969 he was at Lawrence Berkeley Laboratory and later UC Berkeley, where he got his tenure in 1964. He was on leave at Harvard (1966–1967) and MIT (1967–1969), where he became professor of physics (1969–1973) and then moved to Harvard (1973–1983), where he succeeded Julian Schwinger as Higgins Professor of Physics. Weinberg joined the faculty of the University of Texas at Austin as the Josey Regental Professor of Physics in 1982, and remained there for the rest of his life.

Immense contributions

Perhaps his best known contribution to physics is his formulation of electroweak unification in the context of gauge theories and using the Brout–Englert–Higgs mechanism of symmetry breaking to give mass to the W and Z bosons, while sparing the photon (CERN Courier November 2017 p25). The names Glashow, Weinberg and Salam are forever associated with the spontaneously broken SU(2) × U(1) gauge theory, which unified the electromagnetic and weak interactions and provided a large number of predictions that have been experimentally confirmed. The most concise and elegant presentation of the theory appears in Weinberg’s famous 1967 paper: “A Model of Leptons”, one of the most cited papers in the history of physics, and a great example of clear science writing (CERN Courier November 2017 p31). At the time, the first family of quarks and leptons was known, but the second was incomplete. After a substantial amount of experimental and theoretical work, we now have the full formulation of the Standard Model (SM) describing our best knowledge of the fundamental laws of nature. This is a collective journey starting with the discovery of the electron in 1897, and concluding with the discovery of the scalar particle of the SM (the Higgs boson) at CERN in 2012. Weinberg was deeply involved with the building of the SM before and beyond his 1967 paper.

Normal humans would need to live several lives to accomplish so much

It is impossible to do justice to all the scientific contributions of Weinberg’s career, but we can list a few of them. In the early 1960s he embarked on the study of symmetry breaking, and wrote a seminal contribution with Goldstone and Salam describing in detail and in full generality the mechanism of spontaneous symmetry breaking in the context of quantum field theory, providing sound bases to the earlier discoveries of Nambu and Goldstone. Around the same time, he worked out the general structure of scattering amplitudes with the emission of arbitrary numbers of photons and gravitons. It is remarkable that this work has played a very important role in the recent study of asymptotic symmetries in general relativity and gauge theories (for example, Bondi–Metzner–Sachs symmetries and generalisations, and the general theory of Feynman amplitudes).

From jets to GUTs

Together with George Sterman, Weinberg started the study of jets in QCD, whose importance in modern high-energy experiments can hardly be exaggerated. He (and independently Frank Wilczek) realised that in the Peccei–Quinn mechanism invoked to solve the strong-CP problem, there is a light pseudoscalar particle lurking in the background. This is the infamous axion, also a prime candidate for dark-matter particles and whose experimental search has been actively pursued for decades. Weinberg was one of the pioneers in the formulation of effective field theories that transformed the traditional approach to quantum field theory. He was the founder of chiral perturbation theory, one of the initiators of relativistic quantum theories at finite temperature, and of asymptotic safety, which has been used in some approaches to quantum gravity. In 1979 he (and independently Leonard Susskind) introduced the notion of technicolour – an alternative to the Brout–Englert–Higgs mechanism in which the scalar particle of the SM appears as a composite fermion, which some find more appealing, but so far has little experimental support. Finally, we can mention his work on grand unification together with Howard Georgi and Helen Quinn, where they used the renormalisation group to understand in detail how a single coupling in the ultraviolet evolves in such a way that in the infrared it generates the coupling constants of the strong, weak and electromagnetic interactions.

Astronomical arguments

Steven Weinberg also made profound contributions in his work on the cosmological constant. In 1989 he used astronomical arguments to indicate that the vacuum energy is many orders of magnitude smaller than would be expected from modern theories of elementary particles. His bound on its possible value based on anthropic reasoning is as deep as it is unsettling. And it agrees surprisingly well with the measured value, as inferred from observations of receding, distant supernovae. It shatters Einstein’s dream of unification, when he asked himself whether the Almighty had any choice in creating the universe. Anthropic reasoning opens the door to theories of the multiverse that may also be considered as inevitable in some versions of inflationary cosmology, and in the theory of the string landscape of possible vacua for our universe. Among all the parameters of the current standard models of cosmology and particle physics, the question of which are environmental and which are fundamental becomes meaningful. Some of their values may ultimately have only a purely statistical explanation based on anthropism. “It’s a depressing kind of solution to the problem,” remarked Weinberg recently in the Courier: “But as I’ve said: there are many conditions that we impose on the laws of nature, such as logical consistency, but we don’t have the right to impose the condition that the laws should be such that they make us happy!” (CERN Courier March/April 2021 p51). On the one hand, his work led to the unification of the weak and electromagnetic forces; on the other the landscape of possibilities points against a unique universe. The tension between both points of view continues.

Weinberg also mastered the art of writing for non-experts. One of the most influential science books written for the general public is his masterpiece The First Three Minutes (1977), which provides a wonderful exposition of modern cosmology, the expansion of the universe, the cosmic microwave background radiation, and of Big Bang nucleosynthesis. Towards the end of the epilogue he formulated his famous statement that generated heated discussions with philosophers and theologians: “The more the universe seems comprehensible, the more it seems pointless.” In the next paragraph he tempers the coldness somewhat: “The effort to understand the universe is one of the very few things that lifts human life a little above the level of farce, and gives it some of the grace of tragedy.” But the implied meaning that the laws of nature have no purpose continues to be as provocative as when it was made originally. The debate will linger on for a long time. 

Controversies and passions 

Weinberg’s non-technical books exhibit an extraordinary erudition in numerous subjects. His approach is original and thorough, and always illuminating. He did not shy away from delicate and controversial discussions. Weinberg was a declared atheist, with a rather negative opinion on the influence of religion on human history and society. He showed remarkable courage to be outspoken and to engage in public debates about it. Again in his 1977 book, he wrote: “Anything that we scientists can do to weaken the hold of religion should be done and may in the end be our greatest contribution to civilisation.” Needless to say, such statements raised a number of blisters in some quarters. He was also a champion of scientific reductionism, something that was not very well received in many philosophical communities. He was clearly passionate about science and scientific principles, and in defence of the search for truth. In Dreams of a Final Theory (2011) he described his fight to avoid the demise of the Superconducting Super Collider (SSC). His ardent and convincing argument about the value of basic science, and also its importance as a motor of economic and technological growth, were not enough to convince sufficient members of the House of Representatives and the project was cancelled in 1993. It was a very hard blow to the US and global high-energy physics communities. The discussion had another great scientist on the other side: Phil Anderson, who passed away in 2020. It is not obvious if Anderson was against particle physics, or against big science. What is clear is that given the size of the budget deficit in the US (now and then), what was saved by not building the SSC did not go to “table top” science. 

In a 2015 interview to Third Way, Weinberg explained his philosophy and strategy when writing for the general public: “When we talk about science as part of the culture of our times, we would better make it part of that culture by explaining what we are doing. I think it is very important not to write down to the public. You have to keep in mind that you are writing for people who are not mathematically trained, but are just as smart as you are.”  This empathy and respect for the reader is immediately apparent as soon as you open any of his books, and together with the depth and breadth of his insight, explains their success.

He also excelled in the writing of technical books. In the early 1960s Weinberg became interested in astrophysics and cosmology, leading, among other things, to the landmark Gravitation and Cosmology (1971). The book became an instant classic, and it is still useful to learn about many aspects of general relativity and the early universe. In the 1990s he published a masterful three-volume set on The Quantum Theory of Fields, which is probably the definitive treatment on the subject in the 20th century. In 2008 he published Cosmology, an important update of his 1971 work, providing self-contained explanations of the ideas and formulas that are used and tested in modern cosmological observations. He also published Lectures on Quantum Mechanics in 2015, among one of the very best books on the subject, where the depth of his knowledge and insight shine throughout. The man had not lost his grit. Only this year, he published what he described as an advanced undergraduate textbook Foundations of Modern Physics, based on a lecture course he was asked to give at Austin. What distinguishes his scientific books from many others is that, in addition to the care and erudition with which the material is presented, they are also interspersed with all kinds of golden nuggets. Weinberg never avoids some of the conceptual difficulties that plague the subjects, and it is a real pleasure to find deep and inspiring clarifications.

It is not possible to list all his awards and honours, but let’s mention that he was elected to the US National Academy of Sciences in 1972, was awarded the Dannie Heineman Prize for Mathematical Physics in 1977 and the Nobel Prize in Physics in 1979. He was also a foreign honorary member of the Royal Society of London, received a Special Breakthrough Prize in Fundamental Physics in 2020, and has been invited to give the most prestigious lectures on the planet. Normal humans would need to live several lives to accomplish so much.

A great general 

Lately, Weinberg was interested in fundamental problems in the foundations and interpretation of quantum mechanics, and in the study of gravitational waves and what we can learn about the distribution of matter in the universe between us and their sources – two subjects of very active current research. In a 2020 preprint “Models of lepton and quark masses”, he returned to a problem that he last tackled in 1972, the fermion mass hierarchy.

His legacy will continue to inspire physicists for generations to come 

He also continued lecturing until almost the very end. Weinberg was an avid reader of military history, as evidenced in some of his writings, and as with a great general, he died with his boots on.

The news of his demise spread like a tsunami in our community, and led us into a state of mourning. When such a powerful voice is permanently silenced, we are all inevitably diminished. His legacy will continue to inspire physicists for generations to come.

Steven Weinberg is survived by his wife Louise, professor of law at the University of Texas, whom he married in 1954, his daughter Elizabeth, a medical doctor, and a granddaughter Gabrielle.

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An ATLAS researcher and a leading string theorist are among the winners of the 2021 Mustafa prize, which recognises researchers from the Islamic world. Yahya Tayalati (Mohammed V University, Rabat) was cited for contributions to searches for magnetic monopoles and his work on light-by-light scattering, which was first observed by ATLAS in 2019. Cumrun Vafa (Harvard) was recognised for developing F-theory. Among other laureates, M. Zahid Hasan (Princeton) was cited for his work on Weyl-fermion semimetals and topological insulators – materials which are insulators inside but conduct on their surfaces. Each wins $500,000.

Since its foundation in 2012, the Mustafa Prize has been announced every two years. This year is the first time that the prize has been awarded to researchers in fundamental science.

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Panofsky Prize for ν_τ discovery

The American Physical Society (APS) W K H Panofsky Prize in Experimental Particle Physics has been awarded to Byron G Lundberg and Regina Abby Rameika (Fermilab), Kimio Niwa (Nagoya University) and Vittorio Paolone (University of Pittsburgh) “for the first direct observation of the tau neutrino through its charged-current interactions in an emulsion detector”. Lundberg, Rameika Niwa and Paolone were leaders of the DONUT collaboration, which in July 2000 reported evidence of four tau neutrino interactions (with an estimated background of 0.34 events) in a sample of 203 neutrino-nucleus interactions, consistent with the Standard Model expectation. Although earlier experiments had produced convincing indirect evidence for the ν_τ existence, the DONUT/Fermilab result represented the first direct observation.

J J Sakurai Prize

The 2022 APS J J Sakurai Prize has been awarded to Nima Arkani-Hamed (Institute for Advanced Study) for the development of transformative new frameworks for physics beyond the Standard Model “with novel experimental signatures, including work on large extra dimensions, the Little Higgs, and more generally for new ideas connected to the origin of the electroweak scale”. One of the leading particle  phenomenologists of his generation,  Arkani-Hamed has argued that the extreme weakness of gravity relative to other forces of nature might be explained by the existence of extra spatial dimensions, and how the structure of comparatively low-energy physics is constrained within the context of string theory.

Robert R Wilson Prize

In the field of particle accelerators, the Robert R Wilson Prize has been given to Fermilab’s William G Foster and Stephen D Holmes for leadership in developing the modern accelerator complex at Fermilab, enabling the success of the Tevatron program that supports rich programs in neutrino and precision physics. In 2008, three years before the Tevatron closed down, Foster was elected to the US Congress to represent the people of Illinois. Holmes was director of Fermilab’s PIP-II project when he retired in 2018 after 35 years at Fermilab .

Herman Feshbach Prize

The Herman Feshbach Prize was granted to David B Kaplan (University of Washington) for multiple foundational innovations in nuclear theory, including in lattice quantum chromodynamics, effective field theories, and nuclear strangeness, and for strategic leadership to broaden participation between nuclear theory and other fields. Kaplan is director of the Institute for Nuclear Theory at Washington with research interests also including quantum computing, cosmology, and physics beyond the Standard Model.

Henry Primakoff Award

The 2022 APS Henry Primakoff Award for Early-Career Particle Physics has been awarded to Benjamin Nachman of Lawrence Berkeley National Laboratory for innovative contributions to the search for new physics in collider data incorporating original machine learning algorithms, and for the effective communication of these new techniques to the broader physics community. A member of ATLAS, Nachman focuses on track reconstruction inside jets, and is involved in the design of a readout chip for the upgraded ATLAS pixel detector.

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Sheldon Stone, who passed away on 6 October, was one of the foremost physicists of his generation. In terms of creativity and productivity he had few equals in heavy-quark physics worldwide. His skills in leadership, physics analysis and instrumentation served our field well.

Sheldon had a central role in the success of the CLEO experiment at the Cornell Electron Storage Ring, which over a period of almost 30 years laid the foundations for our current understanding of heavy-flavour physics. He served as both CLEO analysis coordinator and co-spokesperson, and had a leading role in many important discoveries such as the observation of the B⁺, B⁰, and D_s mesons. In 2000 he was one of the intellectual leaders who proposed to convert CLEO into a charm factory, subsequently leading the measurement of the charm-decay constants f_D+ and f_Ds. These and other measurements demonstrated the applicability of lattice-QCD calculations of hadronic effects in the weak decays of hadrons with a heavy quark with precision of a few-percent, thereby enabling similar calculations to be used with confidence to interpret key measurements by other flavour-physics experiments worldwide.

His advocacy of the BTeV project at Fermilab was also vital in making the case for a forward flavour-physics detector at a hadron collider

In 2005 Sheldon became a member of the LHCb collaboration, where his and his group’s contribution to the physics exploitation of the experiment was second-to-none. Prominent examples include the first measurement of the beauty-production cross-section at the LHC, and a series of publications measuring CP-violating observables in time-dependent decays of B_s mesons. In 2015 LHCb published the first observation of structures consistent with five-quark resonances – “pentaquarks” which were predicted at the dawn of the quark model but had evaded discovery for over 50 years until Sheldon and a small team of colleagues uncovered their existence in the LHCb dataset. This result has had an enormous impact on the field of hadron spectroscopy.

Sheldon also led the design and construction of novel and high-performance detectors underpinning CLEO’s outstanding physics output. These include a thallium-doped near-4π caesium-iodide calorimeter (the first application of a precision electromagnetic calorimeter to a general-purpose magnetic spectrometer) and a Ring-Imaging Cherenkov Counter providing four-sigma kaon-pion separation over the full accessible momentum range.

His advocacy of the BTeV project at Fermilab was also vital in making the case for a forward flavour-physics detector at a hadron collider. This led him to be heavily involved in shaping phase one of the LHCb upgrade project, serving as upgrade coordinator for three years during the preparation of the Letter of Intent, and recently in making innovative proposals for the phase-two upgrade. At the time of his passing, Sheldon was deputy project leader of the upstream tracker, a project that he and his group proposed and led for a decade, and is currently undergoing final assembly. This silicon-strip based detector will play an essential role in both the triggering and offline event reconstruction from Run 3.

Exceptionally effective at guiding others both junior and senior, Sheldon was a superb mentor to graduate students and a wonderful person to collaborate with. He was known to have a strong personality. He was direct and honest, and if you won his respect he was a tremendous friend.

Sheldon’s contributions to our field were at the highest level, recognised most recently with the American Physical Society Panofsky Prize in 2019. For over 30 years he also formed a formidable scientific and life partnership with physicist Marina Artuso who survives him.

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