New leader at Fermilab’s next accelerator
On 1 March, accelerator physicist Lia Merminga was appointed project director for Fermilab’s PIP II (Proton Improvement Plan II) and its new superconducting linear accelerator. Along with improvements to Fermilab’s Main Injector and Recycler accelerators, PIP II will provide high-intensity proton beams for future experiments including the flagship Long-Baseline Neutrino Facility and the Deep Underground Neutrino Experiment.
The new 800 MeV machine will double the energy of the existing linac at Fermilab and is the first particle accelerator to be built in the US with significant contributions from international partners. Merminga, previously associate laboratory director for accelerators at SLAC National Accelerator Laboratory, succeeds Fermilab’s Stephen Holmes. She has more than 25 years’ experience in accelerator and superconducting radio-frequency technology, and served as director of the Center for Advanced Studies of Accelerators at Jefferson Lab and as head of the accelerator division at Canada’s TRIUMF laboratory.
Change of chairs for antimatter community
Experimentalists Stefan Ulmer of RIKEN and Chloé Malbrunot of CERN have been elected chairperson and deputy chairperson, respectively, of the Antiproton Decelerator (AD) user community. The roles involve representing the interests of the antimatter community to CERN management, requiring regular contact with the spokespersons of approved AD experiments and organising beam time.
The AD is a unique global research facility hosting the AEgIS, ALPHA, ASACUSA, ATRAP, BASE and GBAR experiments. Ulmer is founder and spokesperson of the BASE collaboration, while Malbrunot is involved with ASACUSA and AEgIS. For the past 17 years the AD user community has been represented by Walter Oelert and, since 2012, Horst Breuker.
Pontecorvo award to Fogli and Lisi
The 2017 Bruno Pontecorvo Prize, which is given by the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, has been awarded to Gianluigi Fogli and Eligio Lisi of the University of Bari and INFN in Italy for their pioneering contributions to the development of the global analysis of neutrino oscillation data from different experiments. The announcement followed the approval of an international jury’s recommendations by the JINR scientific council at its 123rd session on 22–23 February.
The work of Fogli, Lisi and the Bari neutrino group on the theory and phenomenology of neutrino and astroparticle physics has led to a detailed understanding of oscillation searches with solar, atmospheric, accelerator and reactor neutrinos, and of their interplay with non-oscillatory searches. The two laureates will report on their achievements at an awards ceremony at the next session of the JINR council on 20–21 September. The Pontecorvo Prize was established in 1995 to commemorate Bruno Pontecorvo, once Enrico Fermi’s collaborator and often deemed the father of neutrino physics.
Gold medal for extreme nuclei
The 2017 Lomonosov Gold Medal, the highest accolade of the Russian Academy of Sciences, has been awarded to Yuri Oganessian of the Joint Institute for Nuclear Research (JINR) in Russia and Björn Jonson of Chalmers University of Technology in Sweden.
The pair has extended our knowledge on nuclei at the extremes of existence in opposite ends of the nuclear chart. Oganessian has made fundamental contributions to the study of superheavy elements, also acknowledged in 2016 when element 118 was named Oganesson (Og), while Jonson, who has also played key roles in CERN’s ISOLDE facility, has focused on the nuclear structure and stability at the boundaries of the nuclear chart for the lightest elements. The award ceremony took place in Moscow on 30 March.
Winners of the 2018 Collide awards revealed
Arts at CERN, a project started in 2001, allows artists from all over the world to spend time at CERN and work alongside particle physicists and engineers. On 22 March the winners of the 2018 Collide International and Collide Geneva awards, organised in collaboration with Arts at CERN, were announced. London-based artist Suzanne Treister won the Collide International award, a three-month artist residency in collaboration with the Foundation for Art and Creative Technology in the UK that will begin in May.
Her investigation, titled Holographic Universe, aims to “explore the artists’ motivations and intentions through the history of art, from cave painting to modernism and global contemporary art”. The Collide Geneva award, a partnership between Arts at CERN and local authorities, was won by Anne Sylvie Henchoz and Julie Lang. The pair will spend three months at CERN during the autumn, further developing their project Space Time Energy, exploring potential analogies between the human body and particles.
Defining technology for tomorrow’s experiments
The scale and technological sophistication of the detectors at the LHC experiments is almost incomprehensible. In addition to several subdetector systems, they contain millions of detecting elements and support a research programme for an international community of thousands of scientists. The volume of data that will be produced during the high-luminosity upgrade of the LHC (HL-LHC) and by future colliders calls for even more sophisticated technologies.
In November 2017, CERN launched a process to define its R&D programme on new experiment technologies from 2020 onwards. The programme covers detector upgrades beyond the HL-LHC phase and includes concepts developed for the Compact Linear Collider (CLIC) and the Future Circular Collider (FCC) study. The first workshop took place at CERN on 16 March and more than 450 physicists and engineers took part.
Beyond the HL-LHC, explained organiser Christian Joram, the landscape of experiments is only vaguely defined and may evolve in different directions. Therefore, the aim is to launch an R&D programme that concentrates on advancing key technologies rather than developing specialised applications.
It has been shown before that developments in detectors for high-energy physics also benefit many other sectors, from healthcare and medical imaging to industry and quality monitoring. As noted by workshop co-organiser and head of CERN’s experimental physics department Manfred Krammer, it is timely to think how industry can be involved in joint R&D efforts.
Detector improvements envisioned for the 2020s and beyond include better electronic readout, modelling and simulation tools, and better computational techniques for reconstructing the recorded information. Increased timing accuracy to mitigate event pile-up in very high-luminosity environments will almost certainly impact the development of all classes of detectors, whether silicon, gas or photodetectors. The challenges of the HL-LHC and future colliders also places tough requirements on readout electronics and fast data links, while advances in data processing and storage are equally important.
Participants also discussed the special facilities and infrastructures needed to test chips under realistic conditions – presenting an impressive number of options on advanced materials, design tools and production technologies, which could change the way we build detectors and boost their performance. R&D into magnet design for future colliders also demands progress in superconducting materials and cables to meet strict strength and cost requirements.
The talks at the March workshop covered a variety of topics reflecting CERN’s diversity and strong collaboration with commercial and academic partners worldwide. They demonstrated that new concepts, manufacturing tools and materials, combined with the development of simulation tools and software, can open a new era in detector technologies.
A second workshop will take place this autumn to review progress.
• Panos Charitos, CERN.
Standard Model gets annual check up at Moriond
The 2018 Moriond sessions took place in La Thuile, Italy, from 10 to 24 March. The annual conference is an opportunity to review the progress taking place over the breadth of particle physics, from B physics to gravitational waves and from advances in electroweak precision tests to exploratory searches for dark matter. The quest for new particles covers an impressive 40 orders of magnitude, from the 10–22 eV region explored via neutron-spin precession to the 13 TeV energy of the LHC and the highest-energy phenomena in cosmic rays.
Anomalies in the decays of beauty quarks found by the LHCb and B-factory experiments continue to entice theorists to look for explanations for these possible hints of lepton non-universalities, and experimental updates are eagerly awaited (CERN Courier April 2018 p23). Progress continues in the field of CP violation in B and D mesons, while quantitative tests of the CKM matrix are being helped by precise calculations in lattice QCD. Progress on leptonic and semi-leptonic D-meson decays was reported from BES-III, while Belle showed hints of the decay B+ → μ+ ν and evidence of isospin violation. In the classic field of rare kaon decays, the CERN SPS experiment NA62 showed its first results, presenting one candidate event for the elusive decay K+ → π+ ν ν– obtained using a novel in-flight technique.
Fundamental parameters of the Standard Model (SM), such as the masses of the top quark and W boson, are being measured with increasing precision. The SM is in very good shape, apart from the long-standing exception of forward–backward asymmetries. These asymmetries are also being studied at the LHC, and precise results continue to be produced at the Tevatron.
Results on top-quark production and properties are constantly being improved, while hadron spectroscopy is as lively as ever, both in the light meson sector (BESIII) and in heavy quarks (BaBar, Belle and LHCb). Data from HERA are still providing new inputs into structure functions, with c and b quarks now being included. Heavy-ion collisions at LHC and RHIC continue to explore the behaviour of the hot, dense quark–gluon plasma, while proton–ion collisions at fixed-target experiments (LHCb) provide useful inputs to constrain Monte Carlo event generators.
The news on the Brout–Englert–Higgs mechanism is good, with progress on many fronts. The amount of new results presented by ATLAS and CMS, including evidence of ttH production, and global combinations of production and decay channels shows that the precision on the couplings between the Higgs and other particles is improving fast. The study of rare decays of the Higgs boson is advancing rapidly, with the H → μ+μ–decay within reach.
The search for heavy resonances is continuing at full speed, with CMS presenting one Z´ analysis employing the full, available LHC data set (77.3 fb–1), including 2017 data. Is supersymmetry hiding somewhere? Several analyses at ATLAS and CMS are now being recast to include more elusive signatures with various amounts of R-parity violation and degenerate spectra, and there is an emerging interest in performing searches beyond narrow-width approximations.
The search for dark matter is on, with WIMP direct searches maturing rapidly (XENON1T) and including novel experiments like DARKSIDE which, with just 20 l of very pure liquid argon, presented a new best limit at low masses. This field shows that, with ingenuity, there is still room to have an impact. Bounds on extremely light axion-like particles were presented by ADMX for QCD axions, and for neutron electric dipole moments. The interplay between these dedicated experiments and the search for directly produced dark matter at the LHC are highly complementary.
The field of neutrinos continues to offer steady progress with new and old puzzles being addressed. The latest results from T2K disfavour CP-conservation at the level of two sigma, while NOvA disfavours the inverted hierarchy at a similar level. A revival of decay-at-rest techniques and the measurement of coherent elastic neutrino–nucleus scattering by COHERENT (CERN Courier October 2017 p8) were noticeable. The search for heavy neutral leptons is taking place at both fixed-target and collider experiments, while reactor experiments (like DAYA BAY and STEREO) are meant to clarify the reactor antineutrino anomaly. The puzzle of sterile neutrinos is not yet completely clarified after 20 years. Deep-sea (ANTARES) and South Pole (IceCube) experiments are now mature, with ANTARES showing, among other things, searches for point-like sources. IceCube presented a brand new analysis looking for tau-neutrino appearance that is competitive with existing results. Neutrinoless double-beta decay experiments are now biting into the sensitivity of the inverted mass hierarchy (CUORE and EXO-200), with promising developments in the pipeline (CUPID).
Completing the programme of the electroweak session was a glimpse into the physics of cosmic rays and gravitation. The sensitivity of AUGER is now such that mapping the origin of the cosmic rays on the sky becomes feasible. With the observation of a binary neutron-star collapse by LIGO and VIRGO, 2017 saw the birth of multi-messenger astronomy.
On the theory side, one continues to learn from the abundance of experimental results, and there is still so much to be learned by the study of the Higgs and further high-energy exploration. SM computations are breaking records in terms of the numbers of loops and legs involved. Electroweak and flavour physics can indicate the way to new physics scales and extend the motivation to search for dark matter at very low energies. The case to study neutrinos remains as compelling as ever, with many outstanding questions still waiting for answers.
• Augusto Ceccucci, CERN.
Industry rises to FCC conductor challenge
Superconductivity underpins large particle accelerators such as the LHC. It is also a key enabling technology for a future circular proton–proton collider reaching energies of 100 TeV, as is currently being explored by the Future Circular Collider (FCC) study. To address the considerable challenges of this project, a conductor development workshop was held at CERN on 5 and 6 March to create momentum for the FCC study and bring together industrial and academic partners.
The alloy niobium titanium is the most successful practical superconductor to date, and has been used in all superconducting particle accelerators and detectors. But the higher magnetic fields required for the high-luminosity LHC (11 T) and FCC (16 T) call for new materials. A potential superconducting technology suitable for accelerator magnets beyond fields of 10 T is the compound niobium tin (Nb3Sn), which is the workhorse of the 16 T magnet-development programme at CERN.
The FCC conductor programme aims to develop Nb3Sn multi-filamentary wires with a critical current-density performance of at least 1500 A/mm2 at 16 T and at a temperature of 4.2 K. This is 30 to 50% higher than the conductor for the HL-LHC, and a significant R&D effort – including fundamental research on superconductors – is needed to meet the magnet requirements of future higher-energy accelerators. The FCC magnets will also require thousands of tonnes of superconductor, calling for a wire design suitable for industrial-scale production at a considerably lower cost than current high-field conductors.
CERN is engaged in collaborative conductor development activities with a number of industrial and academic partners to achieve these challenging targets, and the initial phase of the programme will last for four years. Representatives from five research institutes and seven companies from the US, Japan, Korea, Russia, China and Europe attended the March meeting to discuss progress and opportunities. Firms already producing Nb3Sn superconducting wire for the FCC programme are Kiswire Advanced Technology (KAT); the TVEL Fuel Company working with the Bochvar Institute (JSC VNIINM); and, from Japan, Furukawa Electric and Japan Superconductor Technology (JASTEC), both coordinated by the KEK laboratory. Columbus Superconductor SpA is participating in the programme for other superconducting materials, while two additional companies – Luvata and Western Superconducting Technologies (WST) – expressed their interest in the CERN conductor programme and attended the workshop.
The early involvement of industry is crucial and the event provided an environment in which industrial partners were free to discuss their proposed technical solutions openly. In the past, most companies produced a bronze-route Nb3Sn superconductor, which has no potential to reach the target for FCC. Thanks to their commitment to the programme, and with CERN’s support, companies are now investing in a transition to internal tin processes. Innovative approaches for characterising superconducting wires are also coming out of academia. Developments include the correlation of microstructures, compositional variations and superconducting properties at TU Wien, research into promising internal-oxidation routes at the University of Geneva, phase transformation studies at TU Bergakademie Freiberg and research of novel superconductors for high-fields at SPIN in Genova.
The FCC initiative is of key importance for future high-energy accelerators. Participants agreed that this could result in a new class of high-performance Nb3Sn material suitable not only for accelerator magnets, but also for other large-scale applications such as high-field NMR and laboratory solenoids.
• Panos Charitos, CERN.
On 27 March, seven L’Oréal-UNESCO For Women in Science “international rising talents” visited CERN, following the 20th edition of the international award at a ceremony in Paris. Left to right: Selene Lizbeth Fernandez Valverde from Mexico; Areej Abuhammad from Jordan; Anna Kudryavtseva from Russia; CERN Director-General Fabiola Gianotti; Ibtissem Guefrachi from Tunisia; Yukiko Ogawa from Japan; Danielle Twilley from South Africa; and Hiep Nguyen from Vietnam.
Training tomorrow’s accelerator scientists
More than 100 people attended an event organised by the European Scientific Institute (ESI), Archamps, on 15 February to mark the 25th anniversary of the Joint Universities Accelerator School (JUAS) and the fifth anniversary of its sister school, the European School of Instrumentation in Particle and Astroparticle Physics (ESIPAP). Among them were current and former students of both schools, as well as PhD and technical students from CERN who had participated in JUAS or ESIPAP in recent years.
Overall, more than 1000 physicists and engineers have been trained at JUAS since it was founded. ESI president, Hans Hoffmann, stressed the need for international and interdisciplinary collaboration in order to tackle major societal challenges, and explained how this goal drives the ESI’s thematic schools. Philippe Lebrun, former head of accelerator technologies at CERN and JUAS director since 2017, reiterated that JUAS exists to teach “the science and technology of accelerators, which are specific domains of physics and engineering in their own right, along with their latest developments, to the designers, builders and operators of tomorrow’s machines”.
These thoughts were echoed by ESIPAP director and a long-standing member of the ATLAS collaboration, Johann Collot. Citing the unprecedented international effort under way to reconcile microscopic physics and modern astronomy, he told students they were lucky to be able to focus their imaginations on such a noble task, “which stems from experimentation and whose conclusion will be revealed through experimentation”. In concluding remarks, CERN director of accelerators and technology, Frédérick Bordry, affirmed the importance of JUAS and ESIPAP in preparing the next generation of particle-accelerator and detector scientists, and assured ESI of CERN’s ongoing support.
Recruitment is already underway for the next editions of JUAS and ESIPAP, which will be held at ESI from January to March 2019. Both schools propose an innovative pedagogical approach, with an intensive mix of lectures, tutorials, seminars, group workshops, laboratory visits and practical sessions. They also include practical sessions at CERN and other internationally renowned facilities, such as the European Synchrotron Radiation Facility in Grenoble and Switzerland’s Paul Scherrer Institut.
Find out more at: esi-archamps.eu.
• Bob Holland, ESI.
Sabri Saidam, minister of education and higher education, Palestine, came to CERN on 21 March. He toured the ATLAS visitor centre and CERN Data Centre.
Olga Nachtmannová, state secretary for Slovakia’s ministry of education, science, research and sport, came to CERN on 22 and 23 March. She visited ALICE and met with the CERN-Slovak community.