APS announces 2017 prize recipients
The American Physical Society (APS) has awarded its prizes for 2017, several of which are devoted to the fields of high-energy and nuclear physics. The W K H Panofsky Prize in Experimental Particle Physics went to Michel Della Negra and Peter Jenni, CERN, and Tejinder Virdee, Imperial College London, for their “distinguished leadership in the conception, design and construction of the ATLAS and CMS detectors, which were instrumental in the discovery of the Higgs boson”. The award recognises and encourages outstanding achievements in experimental particle physics.
The J J Sakurai Prize for Theoretical Particle Physics went to Sally Dawson of Brookhaven National Laboratory, John Gunion of the University of California at Davis, Howard Haber of the University of California at Santa Cruz, and Gordon Kane of the University of Michigan, for their instrumental contributions to the theory of the properties, reactions and signatures of the Higgs boson.
Recognising achievements in the physics of particle accelerators, this year’s Robert R Wilson Prize was awarded to James Bjorken, SLAC, Sekazi Mtingwa, Massachusetts Institute of Technology, and Anton Piwinski, DESY, “for the detailed, theoretical description of intrabeam scattering, which has empowered major discoveries in a broad range of disciplines by a wide variety of accelerators, including hadron colliders, damping rings/linear colliders, and low emittance synchrotron light sources”.
In the nuclear-physics domain, the APS Herman Feshbach Prize in Theoretical Nuclear Physics went to Joseph Carlson of Los Alamos National Laboratory, “for pioneering the development of quantum Monte Carlo techniques to solve key problems in nuclear-structure physics, cold-atom physics, and dense-matter theory of relevance to neutron stars”. The Tom W Bonner Prize in Nuclear Physics, meanwhile, was awarded to Charles Perdrisat of the College of William and Mary, “for groundbreaking measurements of nucleon structure, and discovering the unexpected behaviour of the magnetic and electric nucleon form factors with changing momentum transfer”.
Completing the prize tally in the high-energy physics arena, the Dannie Heineman Prize for Mathematical Physics went to Carl Bender of Washington University, for developing the theory of PT symmetry in quantum systems and sustained seminal contributions that have generated profound and creative new mathematics and impacted broad areas of experimental physics.
Marking 15 years of humanitarian mapping
On 11 October, a United Nations programme called UNOSAT, which delivers satellite images to regions affected by natural disaster or conflict, celebrated 15 years of success in helping relief and development organisations. UNOSAT has been hosted by CERN’s IT department since its inception in 2001, and relies on the laboratory’s IT infrastructure – in particular, the Worldwide LHC Computing Grid – to produce maps with a resolution as high as 30 cm. Raw satellite images made available by space agencies and public and private satellite data providers are stored on CERN’s servers and then transformed into legible, downloadable maps. The tool has become essential for arranging aid and sustainable reconstruction such as that required in West Africa since 2014 in the fight against the Ebola epidemic, or currently in the context of the Syrian conflict. “CERN’s support is essential,” says UNOSAT manager Einar Bjorgo. “Without its powerful IT infrastructure, we wouldn’t be able to compile the satellite data we receive to make it usable.”
CERN science on display in Vienna
On 19 October, a new exhibition about particle physics and cosmology, produced in collaboration with the Institute of High Energy Physics of the Austrian Academy of Sciences, opened at the Natural History Museum of Vienna. Called “The beginning of everything”, it promises to take visitors on a journey more than 13 billion years into the past, and to communicate the most recent scientific knowledge of particle physics and cosmology from different visual, optical and acoustic angles and perspectives. Part of the exhibition is devoted to CERN, and the exhibition will run until 1 May 2017.
YITP celebrates 50 years
The C N Yang Institute for Theoretical Physics (YITP) at Stony Brook University in the US celebrated its 50th anniversary with a symposium on 9–10 October. The YITP was founded in 1966, when Chen Ning Yang came to the then almost-unknown Stony Brook University, at the invitation of the university’s president John Toll. Together with Tsung-Dao Lee, Yang shared the 1957 Nobel Prize in Physics for his work on parity non-conservation in weak interactions.
The YITP is associated with several advances in the areas of supergravity, gauge-theory renormalisation, neutrinos and QCD collider theory, in addition to statistical mechanics. A video message from Yang saw the 94 year-old theorist refer to his years at Stony Brook as a “second career” after his time at the Institute for Advanced Study. He recalled the earliest days of supergravity and informal lectures from mathematician James Simons, which eventually “contributed to the increasingly close contact between the world communities of physicists and mathematicians”.
LHC sheds light on extreme cosmic rays
The 19th International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI) took place on 22–27 August in Moscow, Russia, attracting more than 100 physicists. At the core of discussions was the status of our understanding of hadronic particle production as observed in interactions involving cosmic rays, and as measured in accelerator experiments.
The impact of LHC measurements on the interpretation of cosmic-ray data was a central theme. Important general observations of direct relevance to cosmic-ray physics include: the moderate growth of the inelastic cross-section and secondary particle multiplicity; the absence of rapid changes of the particle distributions close to the beamline; and the overall agreement between charm-particle production and perturbative QCD calculations. Thanks to LHC data, the ambiguity in the interpretation of air-shower data of ultra-high-energy cosmic rays has been significantly reduced and a mixed composition of primary elements is now favoured at energies above 1019 eV (previously the data were considered compatible with a flux of only protons). Moreover, good agreement is found between the composition data of the two biggest air-shower detectors, the Pierre Auger Observatory and Telescope Array.
Comparing ALICE data relating to atmospheric muons with state-of-the-art simulations, an excess in high-multiplicity muon bundles previously reported by several LEP experiments has not been confirmed. Still, the muonic component of air showers is a source of many puzzles. For example, the Auger collaboration reported that the measured muon number in air showers with energies of 1019 eV exceeds the model expectations. In addition, the high-statistics data on muon and electron numbers recorded by the KASCADE air-shower array can still not be consistently interpreted with contemporary interaction models – even after accounting for LHC data, which are taken at an energy higher than that of the famous “knee” in the cosmic-ray spectrum (which corresponds to an energy of around 3 × 1015 eV). On the other hand, at lower energies, the muon data from IceTop (the air-shower array located above IceCube) are still bracketed by expectations for proton and iron particles as primaries. Data relating to pion–nucleus interactions taken with fixed-target experiments, such as NA61 at CERN, are expected to help to resolve these muon puzzles.
The high-energy neutrinos measured by IceCube continue to be a focus of this community. Neutrinos produced in interactions of cosmic rays in the atmosphere constitute the dominant background to those from astrophysical sources. Fortunately, the LHC probes the energy region that is most important for understanding this background, which stems mainly from the production and decay of charm particles. Although the good overall agreement of the charm measurements with predictions is very encouraging, it was reported that the LHC measurements cover only about 12% of the phase space needed for calculating PeV-energy neutrino fluxes.
ISVHECRI participants were also reminded of the early pioneering work on particle physics using cosmic-ray interactions recorded with emulsion chambers, which still harbour phenomena that are yet to be understood. The symposium concluded with a discussion of the most important future accelerator measurements needed for improving our understanding of cosmic-ray data. Studying proton interactions with light nuclei at the LHC is top of the wish list, followed by pion–nucleus interactions in fixed-target experiments at the highest energies possible. The next symposium of the biennial ISVHECRI series will take place in Nagoya, Japan, in spring 2018.
CERN sets bar for cryogenic safety
Around 120 experts in cryogenic safety met at CERN on 21–23 September for the first cryogenic-safety seminar. In addition to discussions about best practice and regulatory frameworks, a highlight of the event was a new CERN technology called Kryolize developed for the cryomagnets of the LHC and other CERN facilities.
Kryolize is a software tool tailored for sizing cryogenic pressure-relief devices that protect against overpressure, such as that encountered by the LHC shortly after it switched on in 2008. It is based on international and European standards and was originally conceived to respond to the specific needs of CERN to develop valves for use with liquid helium at extremely low temperatures. The LHC uses an unprecedented 120 tonnes of liquid helium to cool 36,000 tonnes of superconducting magnets to just 1.9 K.
Kryolize is supported by CERN’s Knowledge Transfer group and currently has 30 users at CERN. Six licences have so far been granted to other research laboratories and it is anticipated that, once the project reaches its conclusion in mid-2017, the tool will have applications in domains ranging from the food industry to medicine.
Robert-Jan Smits, director general for research and innovation at the European Commission, is the first recipient of a new award: Recognition of Lifetime Achievements for European Science and Society. Created by EuroScience, an association of researchers in Europe and founder of the EuroScience Open Forum (ESOF), the award cites Smit’s ability to help create new and more effective EU policies and structures, co-ordinate EU tools with national policies and align all of these towards the broader needs of society.
Deep discussions at DIS 2016
The 24th workshop on Deep Inelastic Scattering and related subjects (DIS2016) took place on 11–15 April at DESY in Hamburg, Germany. The event acted as a melting pot for worldwide investigations of the proton structure and strong interactions at the LHC, HERA, Tevatron, RHIC, JLAB, COMPASS and other experiments. It also covered related theory advances, future experiments and results from the high-energy frontier. The workshop was organised into seven separate working groups, and selected highlights from each are given here.
Concerning structure functions and parton densities, the final combined HERA (H1 and ZEUS) inclusive DIS data have had a significant impact on parton-distribution functions (PDFs) and resulting predictions of LHC processes. ATLAS, CMS and LHCb presented the first production measurements of W and Z bosons and of jets made at LHC Run 2, which will help to further constrain the PDFs.
In the electroweak and beyond-the-Standard-Model sector, many final Run 1 results were reported by ATLAS and CMS on the Higgs boson as well as on precision measurements of multiboson production. No deviations from the Standard Model were observed, and it is clear that the community is in need of calculations including next-to-leading order (NLO) electroweak corrections if it is to compete with the LHC’s experimental precision.
A wealth of new LHC results concerning QCD and hadronic final states were presented, which often probe the final-state kinematics in great detail. Theorists are attempting to match the improved experimental precision, for example with generators based on full next-to-next-to-leading order (NNLO) calculations. The description of the underlying event and double-parton scattering was another important topic, with many new experimental and theoretical results being debated.
In the heavy-flavour community, new CMS top-pair production data from Run 2 have been compared to the first complete NNLO QCD predictions for differential distributions, which have only recently become available. These calculations improve the description of the observed top-quark transverse-momentum spectrum and open a new precision era in top physics. Many new beauty and charm results were presented such as the first Run 2 measurements of open-charm production by LHCb.
Regarding low-x, diffraction and vector mesons, theorists propose to carry out extended studies at the LHC with events containing “Mueller–Navelet” jets (two forward jets with a large rapidity gap between them). Several advances were presented on the phenomenology of diffractive vector-meson production at HERA, where the first measurement of the reaction γ + p → ρ0 π+ n was reported by H1. Ultra-peripheral collisions in nuclear collisions at the LHC and RHIC are another hot topic in the low-x community at this time.
Concerning the long-standing spin puzzle – i.e. the question of how the nucleon’s spin is distributed among its constituent partons – new spin-asymmetry results were presented by COMPASS as well as by the PHENIX and STAR experiments at RHIC, adding significant constraints on the quark and gluon spin contributions. COMPASS, HERMES and JLAB also presented new studies of semi-inclusive DIS.
Finally, with regard to future experiments, there is much to look forward to. JLAB will continue its 3D-hadron-imaging studies with a second generation of experiments using its 12 GeV electron beam, while COMPASS and STAR will take further data until 2017. Despite the achievements by these facilities, the lack of experimental information for x ≤ 0.01 remains a severe limitation. As such, there is great hope that the Electron Ion Collider (EIC) project in the US will lead to comprehensive 3D hadron imaging and solve the spin puzzle. On the energy frontier there is also the intriguing opportunity of an electron–ion collider in the envisaged 54 km ring accelerator complex in China. Such machines could provide a unique precision tool for a complete flavour decomposition of the proton structure and would cover a broad spectrum of strong and electroweak physics.
The next DIS workshop will take place in Birmingham, UK, from 3 to 7 April 2017.
Elisabeth Laurin, ambassador and permanent representative of France to the United Nations Office at Geneva and international organisations in Switzerland (right), with CERN Director-General Fabiola Gianotti at the 14th edition of France@CERN on 3–4 October. The annual event welcomed representatives from 37 companies covering a wide range of sectors including engineering mechanics, energy, transport and information technology.
Italian actress Sonia Bergamasco, who’s work includes a role in the 2008 Italian television movie Einstein, visited CERN on 13 October, during which she took in the surroundings of the CERN Control Centre.
Glenys Beauchamp, secretary, Department of Industry, Innovation and Science, Australian government, visited CERN on 26 October and signed the guestbook in the presence of CERN director for international relations Charlotte Warakaulle (left) and Director-General Fabiola Gianotti.