Jobs – Page 58 of 504

Luciano Girardello 1937–2022

Luciano_Girardello_2022 — Luciano was interested in all aspects of fundamental physics, from quantum field theory to gravity. Credit: Family photograph

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.

Patricia McBride elected next CMS spokesperson

patty-mcbride-08-0297-11D — Patricia McBride. Credit: Fermilab

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.”

David Saxon 1945–2022

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.

Commemorating Bruno Touschek’s centenary

touschek_featured_img — Bruno Touschek, pictured here in the 1950s, was one of the first physicists in Europe who was
skilled in elementary particle theory and in functioning of accelerators. Credit: F Touschek

Bruno Touschek was born in Vienna on 3 February 1921. His mother came from a well-to-do Jewish family and his father was a major in the Austrian Army. Bruno witnessed the tragic consequences of racial discrimination that prevented him from both completing his high school and university studies in Austria. But he also experienced the hopes of the post-war era and played a role in the post-war reconstruction. With the help of his friends, he continued his studies in Hamburg, where he worked on the 15 MeV German betatron proposed by Rolf Widerøe and learnt about electron accelerators. After the war he obtained his PhD at the University of Glasgow in 1949 , where he was involved in theoretical studies and in the building of a 300 MeV electron synchrotron. Touschek emerged from the early-post war years as one of the first physicists in Europe endowed with a unique expertise in the theory and functioning of accelerators. His genius was nurtured by close exchanges with Arnold Sommerfeld, Werner Heisenberg, Max Born and Wolfgang Pauli, among others, and flourished in Italy, where he arrived in 1953 called by Edoardo Amaldi, his first biographer and first Secretary-General of CERN.

In 1960 he proposed and built the first electron-positron storage ring, Anello di Accumulazione (AdA), which started operating in Frascati in February 1961. The following year, in order to improve the injection efficiency, a Franco-Italian collaboration was born that brought AdA to Orsay. It was here that the “Touschek effect“, describing the loss and scattering of charged particles in storage rings, was discovered and the proof of collisions in an electron-positron ring was obtained.

AdA paved the way to the electron-positron colliders ADONE in Italy, ACO in France, VEPP-2 in the USSR and SPEAR in the US. Bruno spent the last year of his life at CERN, from where – already quite ill – he was brought to Innsbruck, Austria, where he passed away on 25 May 1978 aged just 57.

touschek_sketch — Bruno Touschek’s playful portrayal of T D Lee and parity violation. Credit: F Touschek

Bruno Touschek’s life and scientific contributions were celebrated at a memorial symposium from 2 to 4 December, held in the three institutions where Touschek has left a lasting legacy: Sapienza University of Rome, INFN Frascati National Laboratories and Accademia Nazionale dei Lincei. Contributions also came from the Irène Joliot-Curie Laboratoire, and sponsorship from the Austrian Embassy in Italy.

In addition to Touschek’s impact on the physics of particle colliders, the three-day symposium addressed the present-day landscape. Carlo Rubbia and Ugo Amaldi gave a comprehensive overview of the past and future of particle colliders, followed by talks about physics at ADONE and LEP, and future machines, such as a muon collider, the proposed Future Circular Collider at CERN and the Circular Electron Positron Collider in China, as well as new developments in accelerator techniques. ADONE’s construction challenges were remembered. Developments in particle physics since the 1960s – including the quark model, dual models and string theory, spontaneous symmetry breaking and statistical physics – were described in testimonies from the universities of Rome, Frascati, Nordita and Collège de France.

Touschek’s direct influence was captured in talks by his former students, from Rome and the Frascati theory group, which he founded in the mid 1960s. His famous lectures on statistical mechanics, given from 1959 to 1960, were remembered by many speakers. Giorgio Parisi, who graduated with Nicola Cabibbo, recollected the years in Frascati after the observation of a large hadron multiplicity in e⁺ e^– annihilations made by ADONE, and the ideas leading to QCD.

The final day of the symposium, which took place at the Accademia dei Lincei where Touschek had been a foreign member since 1972, turned to future strategies in high-energy physics, including neutrinos and other messengers from the universe. Also prominent were the many benefits brought to society by particle accelerators, reaffirming the intrinsic broader value of fundamental research.

Touschek’s life and scientific accomplishments have been graphically illustrated in the three locations of the symposium, including displays of his famous drawings on academic life in Roma and Frascati. LNF’s visitor center was dedicated to Touschek, in the presence of his son Francis Touschek.

Celebrating 20 years of n_TOF

The Neutron Time Of Flight (n_TOF) facility at CERN, a project proposed by former Director General Carlo Rubbia in the late 1990s, started operations in 2001. Its many achievements during the past two decades, and future plans in neutron science worldwide, were the subject of a one-day hybrid event NSTAPP – Neutrons in Science, Technology and Applications organised by the n_TOF collaboration at CERN on 22 November.

At n_TOF, a 20 GeV/c proton beam from the Proton Synchrotron (PS) strikes an actively cooled pure-lead neutron spallation target. The generated neutrons are water-moderated to produce a spectrum that covers 11 orders of magnitude in energy from GeV down to meV. At the beginning, n_TOF was equipped with a single experimental station, located 185 m downstream from the spallation target. In 2014, a major upgrade saw the construction and operation of a new experimental test area located 20 m above the production target to allow measurements of very low-mass samples. Last year, during Long Shutdown 2, a new third-generation, nitrogen-cooled spallation target was installed and successfully commissioned to prolong the experiment’s lifetime by ten years. At the same time, a new close-to-target irradiation and experimental station called NEAR was added to perform activation measurements relevant nuclear astrophysics and measurements in collaboration with the R2E (Radiation to Electronics) project that are difficult at other facilities.

Advancing technology

During 20 years of activities, the n_TOF collaboration has carried out more than 100 experiments with considerable impact on nuclear astrophysics, advanced nuclear technologies and applied nuclear sciences, including novel medical applications. Understanding the origin of the chemical elements through the slow-neutron-capture process has been a particular highlight. The high instantaneous neutron flux, which is only available at n_TOF thanks to the short proton pulse delivered by the PS, provided key reaction rates relevant to big-bang nucleosynthesis and stellar evolution (the former attempting to explain the discrepancy between the predicted and existing amount of lithium by investigating ⁷Be creation and destruction, and the latter determining the chemical history of our galaxy).

Basic nuclear data are also essential for the development of nuclear-energy technology. It was this consideration that motivated Rubbia to propose a spallation neutron source at CERN in the first place, prompting a series of accurate neutron cross-section measurements on minor actinides and fission products. Neutron reaction processes on thorium, neptunium, americium, curium, in addition to minor isotopes of uranium and plutonium, have been all measured at n_TOF. These measurements provide the nuclear data necessary for the development of advanced nuclear systems, such as the increase of safety margins in existing nuclear plants as well as to enable generation-IV reactors and accelerator-driven systems, or even enabling new fuel cycles which reduce the amount of long-lived nuclear species.

Basic nuclear data are also essential for the development of nuclear-energy technology

Contributions from external laboratories, such as J-PARC (Japan), the Chinese Spallation Neutron Source (China), SARAF (Israel), GELINA (Belgium), GANIL (France) and Los Alamos (US), highlighted synergies in the measurement of neutron-induced capture, fission and light-charged-particle reactions for nuclear astrophysics, advanced nuclear technologies, and medical applications. Moreover, technologies developed at CERN have also influenced the creation of two startups, Transmutex and Newcleo. The former focuses on accelerator-driven systems for energy production, for which the first physics validation was executed at the FEAT and TARC experiments at the CERN PS in 1999, while the latter plans to develop critical reactors based on liquid lead.

With the recent technical upgrades and the exciting physics programme in different fields, such as experiments focusing on the breaking of isospin symmetry in neutron-neutron scattering and pursuing its core experimental activities, the n_TOF facility has a bright future ahead.

Costas Kounnas 1952–2022

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.

Shining light on the precision frontier

Lepton_Conference_photo featured — **Faces and places** More than 500 attendees participated in lively discussions on physics, diversity and outreach. Credit: M Gersabeck

The 30^th International Symposium on Lepton Photon Interactions at High Energies, hosted online by the University of Manchester from 10 to 14 January, saw more than 500 physicists from around the world engaged in a broad science programme. The Lepton Photon series dates to the 1960s and takes place every two years. This was the first time the conference was meant to return to the UK in over 50 years, with its original August time slot moved to January due to Covid-19 restrictions. The agenda was stretched to improve accessibility in different time zones. Posters were presented via pre-recorded videos and three prizes were awarded following a public vote.

With 2022 marking the ten-year anniversary of the Higgs-boson discovery, it was appropriate that the conference kicked-off with an experimental Higgs-summary talk. Both the ATLAS and CMS collaborations showcased their latest high-precision measurements of Higgs-boson properties and searches for physics beyond the Standard Model using the Higgs boson as a portal. ATLAS presented a new combination of the Higgs total and differential cross-section measurements in the two-photon and four-lepton channels, while CMS shared the first full Run-2 search for resonant di-Higgs production in several multi-lepton final states.

The LHC experiments continue to demonstrate the power of hadron colliders to test the electroweak sector. Notable new results included the first observation of opposite-charge WWjj production at CMS, the first tri-boson (WWW) observation at ATLAS, and LHCb entering the game of W-boson mass measurements. A highlight of the talks covering QCD topics was a combined fit of the parton distribution function of the proton to differential cross-section measurements from ATLAS and HERA data. A wide range of new-physics searches were presented, including a dark-photon search from ATLAS with the full Run-2 data, and a CMS search for new scalars decaying into final states with Higgs-bosons.

In flavour physics, the pattern of anomalies in rare leptonic and semi-leptonic processes continues to intrigue. Highlights in this area included new tests of lepton universality from LHCb in Λ_b⁰→ Λ_c⁺ℓ^–? decays (ℓ=e, μ, τ) , where the decay involving a τ lepton was observed for the first time, and from Belle in Ω_?⁰→Ω⁻ℓ⁺? decays, where the ratio of the e-μ final-state branching ratios was found to be in agreement with the expectation of unity and where the μ decay had been measured for the first time. Similar studies of rare leptonic decays are now also taking place in the charm sector. The BESIII collaboration tested in one study the e-μ universality in a second decay mode and confirmed its agreement with the Standard Model. Participants also heard about the latest searches for the ultra-rare decay K→π?? from KOTO, searching for the neutral kaon decay mode, and from NA62, which now has a 3.4σ evidence for the charged kaon decay mode.

With the 2021 update on muon g-2 from Fermilab, and with the MEG-II, DeeMe and Mu3e experiments getting ready to search for muon-to-electron transitions, there is much excitement about charged-lepton physics. CP violation in beauty and charm remains a hot topic, with updates from LHCb, Belle and BES-III on D⁰ and B_s oscillations and the CKM angle γ. In all these areas, the theoretical community continues to push the boundaries to make improved predictions. Among other things, theorists presented the latest global fits of Wilson coefficients, and several welcome developments in lattice QCD.

The highlights from the neutrino sector included the low-energy excess search by MicroBooNE and the observation of the CNO cycle of solar neutrinos by Borexino. The latest results from the long-baseline experiments – T2K and recently NovA– are starting to hint at large CP violating effects in neutrino oscillations.

A series of talks on dark-matter searches spanned collider experiments, direct detection and astrophysical signatures. Some interesting anomalies persist, such as the DAMA annual modulation and the XENON1T low-energy excess. These will be challenged by a suite of next-generation detectors, such as PANDAX-4T, XENONnT, LZ and DarkSide-20k.

The conference also included a rich programme of talks covering astrophysics with an emphasis on gravitational waves and multi-messenger astronomy. Hot-off-the-press was a combined search for spatial correlations between neutrinos and ultra-high energy cosmic rays, using data from ANTARES, IceCube, Auger and TA collaborations, with no sign yet of a connection.

As well as many new results from experiments in operation, the conference included sessions devoted to R&D in accelerators, detectors, software and computing, covering both collider and non-collider experiments. With many new facilities proposed in the medium and long terms, technological challenges, which include power consumption, data rates and radiation tolerance, are immense and demand significant efforts in harnessing promising avenues such as high-temperature superconductors, quantum sensors or specialised computer accelerators. Common to all areas is the need to train and retain highly skilled people to lead these efforts in future.

A firm part of the Lepton Photon plenary programme are discussions around diversity, inclusion and outreach. A lively panel discussion covered many aspects of the former two topics and ended with a key message to the whole community: be an ally and take an active stance in support of minorities. The conference ended with traditional reports from the IUPAP commission on particles and fields and from ICFA, followed by strategy updates from Snowmass and the African Strategy for Fundamental and Applied Physics. While Snowmass is an established process for regular updates of the US strategy for the field based on wide-spread community input both from the US and internationally, the African strategy is the first of its kind and is testament to the continent’s ambition and growing importance in physics research. The next conference will take place in Melbourne in July 2023.

Ronald Shellard 1948–2021

2021-12-07-1169 Shellard — Ronald Shellard was a long-time proponent of Brazil joining CERN as an Associate Member State. Credit: LIP

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.

Snowmass promises bright future

The University of Washington, Seattle, where the Snowmass21 community study will conclude in July. Image: S. Hopkins

Every seven to 10 years, the US high-energy physics community comes together to re-evaluate and update its vision of the field. These wide-ranging exercises, organised by the American Physical Society (APS)’s Division of Particles and Fields (DPF) since 1982, are now known as the Snowmass Community Studies on account of the final drafting having historically taken place in Snowmass, Colorado. They include all related disciplines that contribute to elementary particle physics and welcome the participation of physicists from outside the US.

Snowmass exists to identify the physics issues that should be addressed and possible approaches to pursuing them, but we do not seek to specify which projects should be carried out. That task is accomplished by a Particle Physics Project Prioritization Panel (P5), a subpanel of the US High Energy Physics Advisory Panel (HEPAP), which uses the Snowmass output to develop programmatic priorities based on specific budget scenarios and provides recommendations to US funding agencies. Snowmass 2013 and the subsequent 2014 P5 roadmap recommended a suite of new projects, including: the HL-LHC upgrade; DUNE/LBNF; a short-baseline neutrino programme; the PIP-II proton source upgrade; the Mu2e experiment; the LSST camera and DESI; the LUX-ZEPLIN and CDMS dark matter searches; preparation for a new cosmic-microwave-background explorer; and strong investment in R&D for future accelerators. With many of these projects now under construction, it is vital to prepare the next round of compelling US particle-physics initiatives.

In April 2020 we kicked off a new Snowmass study. Initially scheduled to conclude with a workshop at the University of Washington in Seattle in July 2021, the process was paused due to COVID-19. On 24 September, at a virtual “Snowmass Day” meeting, we declared the Snowmass process officially resumed, with the Seattle workshop scheduled for 17 to 26 July.

White papers describing ideas, proposals and projects are due by 15 March for discussion

The Snowmass 2021 study is divided into 10 “frontiers”: energy; neutrino physics; rare processes and precision measurements; cosmic; theory; accelerator; instrumentation; computation; underground facilities; and community engagement. Each frontier is led by two or three conveners and is divided into between six and 11 topical groups – with community development, demographics, and diversity and inclusion addressed across all frontiers. A Snowmass early-career organisation has also been formed to assist young physicists in contributing to the process. The whole exercise is overseen by a steering group, which includes the DPF chair line, and international representation is provided by an advisory group chosen by national and regional physics societies.

Informing Snowmass 2021 are many recent results: Higgs-boson properties obtained by ATLAS and CMS; the measurement of the angle θ₁₃ in the neutrino mixing matrix; evidence for anomalies in B-meson decays from LHCb; and the tension between Fermilab’s measurement of muon g-2 and the Standard Model prediction. These topics will continue to be explored in current experiments. Snowmass 2021 and the latest European strategy update focus on what comes next.

Collider matters

In the Snowmass process, we collect all ideas, whether they are large or small, expensive or less so, require international collaboration or not, and are hosted in the US or elsewhere. One topic of intense interest worldwide is the next generation of colliders, both to study the Higgs boson with sub-percent level precision and to directly search for new phenomena in the multi-TeV regime. The proposed Higgs factories require some final development that could be completed in a few years, which would enable a decision on which machine to build, and the start of negotiations to fund it, as an international project. Machines to explore the multi-TeV terrain require significantly more R&D to develop and industrialise the necessary new technologies. We expect this Snowmass/P5 process to set the direction for US participation in this R&D effort and future construction projects. We also look forward to new experiments and upgrades to existing experiments in neutrino physics, rare decays and astrophysics, along with new R&D initiatives in detectors, computing, accelerators and theory.

White papers describing ideas, proposals and projects are due by 15 March 2022 for discussion at the Seattle meeting, where a draft report will be produced and then submitted to HEPAP and the APS in the fall. With hard work and good will, we expect to emerge from the Snowmass/P5 process with a grand vision for a vibrant US high-energy physics programme over the 10 years starting from 2025 and with a roadmap for large new initiatives that will come to fruition in the 2030s. Please join us and contribute your ideas to shaping our future!

Connecting CERN and South Asia

The decision by CERN in 2010 to introduce a policy of geographical enlargement to attract new Member States and Associate Member States, including from outside Europe, marked a prominent step towards the globalisation of high-energy physics. It aimed to strengthen relations with countries that can bring scientific and technological expertise to CERN and, in return, allow countries with developing particle-physics communities to build capacity. From South Asia, researchers have made significant contributions to pioneering activities of CERN over the past decades, including the construction of the LHC.

The first CERN South Asian High Energy Physics Instrumentation (SAHEPI) workshop, held in Kathmandu, Nepal, in 2017, came into place shortly after Pakistan (July 2015) and India (January 2017) became CERN Associate Member States and follows similar regional approaches in Latin America and South-east Asia. Also, within the South Asia region, CERN has signed bilateral international cooperation agreements with Bangladesh (2014), Nepal (2017) and Sri Lanka (2017). The second workshop took place in Colombo, Sri Lanka, in 2019. SAHEPI’s third edition took place virtually on 21 October 2021, hosted by the University of Mauritius in collaboration with CERN. Its aim was to consolidate the dialogue from the first two workshops while strengthening the scientific cooperation between CERN and the South Asia region.

“SAHEPI has been very successful in strengthening the scientific cooperation between CERN and the South Asia region and reinforcing intra-regional links,” said Emmanuel Tsesmelis, head of relations with Associate Members and non-Member States at CERN. “SAHEPI provides the opportunity for countries to enhance their existing contacts and to establish new connections within the region, with the objective of initiating new intra-regional collaborations in particle physics and related technologies, including the promotion of exchange of researchers and students within the region and also with CERN.”

Rising participation

Despite its virtual mode, SAHEPI-3 witnessed the largest participation yet, with 210 registrants. Representatives from Afghanistan, Bangladesh, Bhutan, India, Maldives, Mauritius, Nepal, Pakistan, and Sri Lanka attended, with at least one senior scientist and one student from each country. The workshop brought together physicists and policy makers from the South Asia region and neighbouring countries, together with representatives from CERN. Societal applications of technologies developed for particle physics were key highlights of SAHEPI-3, explained Archana Sharma, senior advisor for relations with international organisations at CERN:

“In this decade, disruptive innovation underpinning the importance of science and technology is making a huge impact towards the United Nations Sustainable Development Goals. CERN plays its role at the forefront, whether it is advances in science and technology or dissemination of that knowledge with an emphasis on inclusive engagement. We see the percolation of this initiative with increasing engagement from the region in CERN programmes.”

Participants reviewed the status and operation of present facilities in particle physics, and the scientific experimental programme, including the LHC and its high-luminosity upgrade at CERN, while John Ellis captivated participants with his talk “Answering the Big Question: From the Higgs boson to the dark side of the Universe”. Sanjaye Ramgoolam topped off the workshop with a public lecture on “the simple and the complex” in elementary particle physics.

SAHEPI has been very successful in strengthening the scientific cooperation between CERN and the South Asia region and reinforcing intra-regional links
Emmanuel Tsesmelis

Country representatives presented several highlights of the ongoing experimental programmes in collaboration with CERN and other international projects. India’s contributions across the ALICE experiment (such as the development of the photon multiplicity detector), its plans to join the IPPOG outreach group, its activities for the Worldwide LHC computing grid, industrial involvement and contributions to CMS – where it is the seventh-largest country in terms of the number of members – were presented. For Afghanistan, representatives described the participation of the country’s first student in the CERN Summer Student School (2019) and the completion of master’s degrees by two faculty members based on measurements at ATLAS. The country hopes to team up with particle physicists outside Afghanistan to teach online courses at the physics faculty at Kabul University, provide postgraduate scholarships to students and involve more female faculty members at ICTP – the International Centre for Theoretical Physics.

Pakistan shared its contributions to the LHC experiments as well as accelerator projects such as CLIC/CTF3 and Linac4 and its role in the tracker alignment of CMS and Resistive Plate Chambers. Nepal representatives described the development of supercomputers at Kathmandu University (KU) and acknowledged the donation agreement between KU and CERN receiving servers and related hardware to set up a high-performance computing facility. In Sri Lanka, delegates highlighted a rising popularity of the CERN Summer Student Programme among university physics students following honours degrees. The country also mentioned its initiative of an island-wide online teacher training programme to promote particle physics. The representative from Bangladesh reported on the country’s long tradition in theoretical particle physics and plans for developing the experimental particle physics community in partnership with CERN. Maldives and Bhutan continue to be growing members from South Asia at CERN, with Bhutan preparing to host the second South Asia science education programme in a hybrid-mode this year.

Strengthening relations
Chief guest Leela Devi Dookun-Luchoomun, the Vice-Prime Minister and Minister of Education, Tertiary Education, Science and Technology of Mauritius, informed the audience about the formation of a research and development unit in her ministry and gave her strong support to a partnership between CERN and Mauritius. The Vice-Chancellor of the University of Mauritius, Dhanjay Jhurry, expressed his deep appreciation of SAHEPI and indicated his support for future initiatives via a partnership between CERN and the University of Mauritius.

The workshop and the initiative to reinforce particle-physics capacity in the region also form part of broader efforts for CERN to emphasise the role of fundamental research in development, notably to advance the United Nations Sustainable Development Goals agenda. In this regard, discussions took place for a follow-up on the first-of-its-kind professional development programme for high-school teachers of STEM subjects from South Asia, held in New Delhi in 2019, with Bhutan volunteering to host the next event in 2023 pandemic permitting. A poster competition engaged students from South Asia, and three prizes were announced to encourage further participation in big-science projects and towards capacity building in the local regions.

The motivation and enthusiasm of SAHEPI-participants was notable, and the efforts in support of research and education across the region were clear. Proceedings of the workshop will be presented to representatives of the governments from the participating countries to raise awareness at the highest political level of the growth of the community in the region and its value for broader societal development.

Discussions will follow in 2023 at SAHEPI-4, helping CERN continue to engage further with particle physics research and education across South Asia for the benefit of the field as a whole.

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