News Article | May 19, 2017
One of the most brilliant theorists of his time, Pierre Binétruy, passed away on 1 April. Binétruy received his doctorate on gauge theories in 1980 under the direction of Mary K Gaillard, and held several positions including a CERN fellowship and postdocs in the US. In 1986, he was recruited as a researcher at LAPP in Annecy-le-Vieux and, four years later, he moved to the University of Paris XI. Since 2003 he was a professor at Paris Diderot University. He helped to found the Astroparticle and Cosmology Laboratory (APC) in 2005 and was its director until 2013. We also owe to him the involvement of the APC in space sciences, Earth sciences, and the realisation of the importance of data science. Binétruy’s research interests evolved from high-energy physics (notably supersymmetry) to cosmology and gravitation, and in particular the intersection between the primordial universe and fundamental theories. His recent interests included inflation models, dark energy and gravitational-wave cosmological backgrounds. During his prolific career, he published seminal papers that approached 1000 citations each and received several awards, including the Thibaud Prize and the Paul Langevin Award. But he will also be remembered for his spirit and courage. He knew that it was necessary not only to seek scientific truth but also to have the courage to prepare the community for the scientific goals that this truth demands and to fight to defend them. Older members of IN2P3 remember the extraordinary intellectual atmosphere that animated the Supersymmetry Research Group, which he proposed and directed from 1997 to 2004, transforming it into an unprecedented crossroads for experimenters and theorists. By that time, when the detection of gravitational waves was for many a distant dream, he also had the intuition to involve France in the field of gravitational-wave detection via the LISA Pathfinder programme – a scientific choice to which he devoted great dynamism right up to his death. Binétruy was also an inspiration to hundreds of students. Through the MOOC Gravity project, which he developed in collaboration with George Smoot, his courses reached tens of thousands of students. He viewed MOOC not just as a simple way to improve the visibility of the university, but as a revolution in the way knowledge is diffused. In parallel with these activities, Binétruy found time to be president of the Fundamental Physics Advisory Group (2008–2010) and the Fundamental Physics Roadmap Committee (2009–2010) of ESA; the French consortium of the LISA space mission; the theory division of the French Physical Society (1995–2003); and the theory section of CNRS (2005–2008). He was also a member of the IN2P3 Scientific Committee (1996–2000) and numerous other panels. Alongside his scientific activities, which he pursued with enthusiasm and unfailing rigor, Binétruy had a deep appreciation and knowledge of broader culture. He had a profound knowledge of the arts, where he was the driving force behind several interactions between art and science. As one of his eminent colleagues said of him: “Pierre was one of those very exceptional people who was at the top of the game and, at the same time, a remarkably pleasant colleague.” Our mentor, colleague and close friend Gösta Ekspong passed away peacefully on 24 February at the age of 95. His life as a particle physicist covered the nuclear-emulsion epoch, the bubble-chamber years, experiments at CERN’s Large Electron–Positron (LEP) and Super Proton Synchrotron colliders. In his retirement he closely followed the results from the LHC, in particular the search for the Higgs boson. In 1950 Ekspong was working with Cecil Powell’s group in Bristol, UK, which had become a world-leading centre for cosmic-ray emulsion work. In a brilliant experiment with Hooper and King he identified the decay π0 → γγ. By observing e+e– pairs from the conversion of the photons close to cosmic-ray interactions, it was possible to determine the mass of the π0 and set an upper limit for its lifetime. Ekspong obtained his doctorate at Uppsala University, Sweden, in 1955, and immediately took up a postdoc position in Emilio Segré’s group at Berkeley where he was involved in the discovery of the antiproton at the Bevatron. Scanning emulsions one evening, he found the first evidence for an annihilation interaction in an emulsion, and on the 50th anniversary of the discovery of the antiproton he was invited to Berkeley to talk about the discovery. Ekspong was appointed to the first chair in particle physics in Sweden, at Stockholm University, in 1960. There he founded a large particle-physics group that over the years made important contributions to many experiments with data mostly from CERN. He strongly supported the use of CERN, where he was a member and chair of the Emulsion Committee in the early 1960s and a member of the Scientific Policy Committee from 1969 to 1975. He was Swedish delegate to CERN Council for many years and was a catalyst for the development of Swedish particle physics. He was elected to the Royal Swedish Academy of Sciences in 1969 and was a member of its Nobel Committee for physics from 1975 to 1988, chairing the committee from 1987 to 1988. His deep knowledge of statistics allowed Ekspong to clarify general features of high-energy interactions. Data from CERN’s Proton Synchrotron and bubble chambers had suggested that the multiplicity distributions of charged particles obeyed so-called “KNO” scaling, but this relationship was found not to be valid in later collider data recorded at higher energies with the UA5 experiment. In a discovery reported and discussed by him at many conferences, Ekspong showed that the distributions instead followed a negative binomial distribution. In the early studies of physics possibilities at the planned LEP collider, Ekspong also made a convincing contribution to the search strategy for observing the Higgs boson by carefully examining the experimental mass resolution. This strategy was later employed by the LEP experiments to exclude the Higgs mass up to about 115 GeV. He also took part in the technical development of one of the LEP experiments, DELPHI. Gösta Ekspong inspired many with his lectures, discussions, and stories about Nobel-prize discoveries. In many articles in Swedish he made physics available and understandable for the general public. Gareth Hughes joined the high-energy physics group at Lancaster University in 1970, following his undergraduate and postgraduate studies at Oxford University. He was born in Wales and was a proud supporter of the Welsh Rugby Union team, although he had never played the game. He used to say that he was among the few Welshmen who never played rugby, who could not sing and who did not like leeks. Ironically, he died on the feast day of St David, the patron saint of Wales. Following his appointment in Lancaster, Gareth played a central role in the work of the Manchester–Lancaster experiment (dubbed “Mancaster”) at Daresbury Laboratory to study the electro-production of nucleon resonances (by which the components of the nucleon are converted to more highly energetic states). He subsequently went on to work on the JADE experiment at DESY, the ALEPH and then ATLAS experiments at CERN – all of which have been key in establishing the Standard Model of particle physics. Gareth’s main strength was computing. In the 1990s, as well as being a member of the CERN Central Computing Committee, he was chairman of the committee that produced the policy on computing for UK particle physics. This was a very rapidly changing field at the time but a subject in which Gareth’s insight and guidance was to prove invaluable. He was also a prominent member of the Particle Physics Grants Committee and other bodies that manage funding for UK particle physics. He was an excellent teacher, his gentle sense of humour and infinite patience making him a much sought after member of staff by both undergraduate and postgraduate students. He eventually became director of undergraduate courses within the physics department at Lancaster. Gareth’s quick grasp of a situation and clear insight made him an extremely valuable colleague with whom to discuss problems. He was widely known and, in turn, seemed to know everyone. This proved to be a great help on numerous occasions. He retired from the physics department in 2007 but continued his involvement with the ATLAS experiment as an emeritus staff member until his death following a short illness. He will be sorely missed by us all but especially by his wife Jane, daughter Siân and son Owain, and his four grandchildren. Thomas Massam received his undergraduate degree in physics in 1956 at the Chadwick Laboratory, Cambridge, and his PhD at the University of Liverpool in 1960. Jovial but very serious and tireless at work, Tom devoted his life to experimental-physics research and to his family. I had the privilege of meeting Tom at the Fermi Summer School of Physics in Varenna, Italy, in 1962. The topics discussed at the school were the results of the Blackett group on the unexpected V particles, later called “strange” by Gell-Mann, and the effects of “virtual physics” in properties of the elementary particles and the experimental-plus-theoretical research needed. Tom was the most active student of the school, and soon afterwards he joined my group at Bologna University and remained there until his retirement in 2002. Together we performed experiments in all of the important laboratories in Europe, including CERN, DESY, ADONE and Gran Sasso. Tom had an extraordinary intelligence, work capacity and “scientific fidelity”. He is also one of the founders of the Ettore Majorana International Centre for Scientific Culture, established at CERN in the early 1960s with its headquarters in Erice, Sicily. In 1972, Tom initiated an International School of Theory Application of Computers. Tom played a major role, contributing with his extraordinary experimental talents, in experiments that established evidence for the Standard Model during the 1960s and afterwards. He helped to set up the first large-scale non-bubble-chamber facility at CERN, and was a close collaborator in our adoption of electromagnetic calorimeters as a tool to separate leptons from hadrons to allow searches for new particle states. Together, we started the first heavy-lepton search and developed a new technology to measure the time-of-flight of particles with a very high precision, leading to the first experimental observation of anti-deuteron production. Tom, research director in the INFN unit of Bologna, was also giving regular physics courses to the students at the ISSP International School of Subnuclear Physics in Erice, established in 1963. Tom is no longer with us. On 1 December 2016 he left his beloved family, Veronica with three children Peter, Steven, Paul, and his friends and colleagues with the unforgettable memory of his extraordinary life. Arthur H Rosenfeld, a long-time member of the faculty at the University of California, Berkeley, and distinguished senior scientist at the Lawrence Berkeley National Laboratory, passed away in Berkeley on 27 January at the age of 90. A student of Enrico Fermi, he was a leading participant in the revolutionary advances in particle physics in the 1950s and 1960s before striking out in a new direction, where he became legendary. A fitting tribute to Art was the award in 2006 of the Enrico Fermi Award of the US Department of Energy “for a lifetime of achievements ranging from pioneering scientific discoveries in experimental nuclear and particle physics to innovations in science, technology, and public policy for energy conservation that continue to benefit humanity. His vision not only underpins national policy but has helped launch an industry in energy efficiency”. Art’s first impact on the physics community was with Jay Orear and Robert Schluter, when the three of them produced the book Nuclear Physics consisting of the notes from Fermi’s course at the University of Chicago. Art came to Berkeley from Chicago and was part of Luis Alvarez’s team, which used bubble chambers to discover many of the meson and baryon resonances, including the omega meson and the Σ*(1385), which led to the recognition of SU(3) flavour symmetry. Art co-authored papers not only with experimenters, but also with Murray Gell-Mann, Shelly Glashow, and Sam Treiman. The 1957 Annual Review of Nuclear Science paper with Gell-Mann, “Hyperons and Heavy Mesons (Systematics and Decay)”, was the beginning of the Particle Data Group. Today’s Particle Data Group and the Review of Particle Physics are, 60 years later, Art’s legacy to the physics community. Much greater still is Art’s legacy to the US and international communities, which benefit today from his relentless pursuit of increased efficiency in the use of energy through both technological advances and political advocacy. The oil embargo of 1973 led Art to wonder why he saw so many obviously wasteful practices in the use of energy. He devoted the rest of his career to rectifying this. That per-capita usage of energy in California remained essentially constant from 1973 to 2006, while it rose by 50% elsewhere in the US, was given the name “The Rosenfeld Effect,” because of Art’s success in getting the state to adopt policies encouraging efficient use of energy. Art, together with a number of nuclear and particle physicists, and with the backing of Andrew Sessler, the director of the Lawrence Berkeley Laboratory in the mid-1970s, developed programmes in energy efficiency for buildings, appliances and lighting, which became a major part of the Laboratory’s programme. Art’s efforts extended beyond the laboratory. He was a founder of the American Council for an Energy-Efficient Economy, a non-profit organisation that continues today to push for policies that increase energy efficiency. Art served in the Clinton administration from 1994 to 1999 as senior adviser to the DOE’s assistant secretary for energy efficiency and renewable energy, and subsequently as commissioner at the California Energy Commission under two state administrations. Among the numerous honours Art received was the National Medal of Science and of Technology and Innovation presented by president Barack Obama in 2011 for “extraordinary leadership in the development of energy-efficient building technologies and related standards and policies”. Art showed that the analytical skills and pragmatism the physics community values could be put to use on practical problems facing humanity. The result of his dedication was profound and lasting contributions to energy efficiency. Despite Art’s ever growing fame, he remained an unassuming colleague, and we remember him as a friend whose achievements transcended the scope of our ordinary research endeavours. Durga Prasad Roy, or DP as he was popularly known, passed away on 17 March in Cuttack, India, after a brief illness. He was active until his last days, having posted a review on the arXiv preprint server in August 2016, participated in conferences in 2017 and having given a series of lectures on the Standard Model at the University of Hyderabad just a few days before he fell ill. DP completed his PhD in particle physics in 1966 at the Tata Institute of Fundamental Research (TIFR), Mumbai, and was a postdoctoral fellow at the University of California (1966–1968), CERN (1968–1969) and the University of Toronto (1969–1970). He moved to the Rutherford Laboratory in the UK (1970–1974), and was a reader at Visva Bharati University, India, from 1974 to 1976. He joined TIFR in 1976 and retired 30 years later in 2006. He then became a member of the Homi Bhabha Centre of Science Education. Scientifically, DP had an instinct for recognising what is important. He made pioneering contributions in particle- and astroparticle-physics phenomenology. His early research work was in the area of “Regge phenomenology and duality”, which addresses the dominant part of cross-sections for hadron–hadron collision processes. Using these ideas, DP predicted exotic mesons called baryonium (now termed tetraquarks) as well as exotic pentaquark baryons – robust predictions that continue to attract the attention of experimentalists and lattice-QCD experts. Along with his collaborators, he suggested to look for a hard isolated lepton and jets as a signature of the top quark, a methodology widely adopted at the CERN and Tevatron proton–antiproton colliders. He also worked extensively on many popular theories of physics beyond the Standard Model, such as supersymmetry. He suggested a promising signature with which to search for charged Higgs bosons using tau decays and the distinctive polarisation of these particles, which is currently being used in the ongoing search for charged Higgs boson at the LHC. Likewise, the missing transverse-momentum signature for supersymmetric particles suggested by DP is being widely used in the ongoing collider searches for these particles. DP and collaborators, and other groups, employed global fits of the solar-neutrino data, including the SNO neutral-current data from 2002, to pin down the large-mixing-angle (LMA) Mikheyev–Smiron–Wolfenstein (MSW) solution to the solar-neutrino problem. This was tested by two impressive sets of neutrino-spectrum results published by the KamLAND experiment in 2003 and 2004. Incorporating these data further in their analysis, and focussing on the LMA–MSW solution in the two-neutrino framework, DP and collaborators ruled out the high-mass-squared-difference LMA solution by more than three standard deviations and converged on the low-mass-squared difference LMA as the unique solution. His scientific achievements were recognised by the Meghnad Saha Award and the SN Bose Medal. He was elected fellow of the Indian Academy of Sciences, Indian National Science Academy and National Academy of Sciences. Along with his colleague Probir Roy, DP started a series of workshops in high-energy physics phenomenology called WHEPP that still initiate a lot of collaborative work today. He was passionate about undergraduate teaching, but also had many interests outside science. He was a weightlifting champion of Orissa, an expert swimmer, and a connoisseur of Indian classical music and dance. His passion for adventure always showed up in the after-work evening activities at WHEPP workshops. He also had strong views on the lack of experimental investigations in ancient India, and published them in an article in the Indian Journal of History of Science in 2016.
News Article | May 19, 2017
On 4 April, CERN alumnus Tim Berners-Lee received the 2016 A M Turing Award for his invention of the World Wide Web, the first web browser, and the fundamental protocols and algorithms allowing the web to scale. Named in honour of British mathematician and computer scientist Alan Turing, and often referred to as the Nobel prize of computing, the annual award of $1 million is given by the Association for Computing Machinery. In 1989, while working at CERN, Berners-Lee wrote a proposal for a new information-management system for the laboratory, and by the end of the following year he had invented one of the most influential computing innovations in history – the World Wide Web. Berners-Lee is now a professor at Massachusetts Institute of Technology and the University of Oxford, and director of the World Wide Web Consortium and the World Wide Web Foundation. The International Centre for Theoretical Physics 2016 Dirac Medal has been awarded to Nathan Seiberg of the Institute for Advanced Study in Princeton, and Mikhail Shifman and Arkady Vainshtein of the University of Minnesota. The award recognises the trio’s important contributions to field theories in the non-perturbative regime and in particular for exact results obtained in supersymmetric field theories. The second edition of the Guido Altarelli Award, given to young scientists in the field of deep inelastic scattering and related subjects, was awarded to two researchers during the 2017 Deep Inelastic Scattering workshop held in Birmingham, UK, on 3 April. Maria Ubiali of Cambridge University in the UK was recognised for her theoretical contributions in the field of proton parton density functions, and in particular for her seminal contributions to the understanding of heavy-quark dynamics. Experimentalist Paolo Gunnellini of DESY, who is a member of the CMS collaboration, received the award for his innovative ideas in the study of double parton scattering and in Monte Carlo tuning. Four members of the IceCube neutrino observatory, based at the South Pole, have independently won awards recognising their contributions to the field. Aya Ishihara of Chiba University in Japan was awarded the 37th annual Saruhashi Prize, given each year to a female scientist under the age of 50 for exceptional research accomplishments. This year’s prize, presented in Tokyo on 27 May, cites Ishihara’s contributions to high-energy astronomy with the IceCube detector. Fellow IceCube collaborator Subir Sarkar of the University of Oxford, UK, and the Niels Bohr Institute in Denmark has won the 4th Homi Bhabha prize. Awarded since 2010 by the Tata Institute of Fundamental Research (TIFR) in India and the International Union of Pure and Applied Physics, the prize recognises an active scientist who has made distinguished contributions in the field of high-energy cosmic-ray and astroparticle physics over an extended academic career. Sarkar has also worked on the Pierre Auger Observatory and is a member of the Cherenkov Telescope Array collaboration. Meanwhile, former IceCube spokesperson Christian Spiering from DESY has won the O’Ceallaigh Medal for astroparticle physics, awarded every second year by the Dublin Institute for Advanced Studies. Spiering, who led the collaboration from 2005 to 2007 and also played a key role in the Lake Baikal Neutrino Telescope, was honoured “for his outstanding contributions to cosmic-ray physics and to the newly emerging field of neutrino astronomy in particular”. Both he and Sarkar will receive their awards at the 35th International Cosmic Ray Conference in Busan, South Korea, on 13 July. Finally, IceCube member Ben Jones of the University of Texas at Arlington has won the APS 2017 Mitsuyoshi Tanaka Dissertation Award in Experimental Particle Physics, for his thesis “Sterile Neutrinos in Cold Climates”. An awards ceremony took place at CERN on 3 April recognising companies that have won contracts to start building the prototype phase of the Helix Nebula Science Cloud (HNSciCloud). Initiated by CERN in 2016, HNSciCloud is a €5.3 million pre-commercial procurement tender driven by 10 leading research organisations and funded by the European Commission. Its aim is to establish a European cloud platform to support high-performance computing and big-data capabilities for scientific research. The April event marked the official beginning of the prototype phase, which covers the procurement of R&D services for the design, prototype development and pilot use of innovative cloud services. The three winning consortia are: T-Systems, Huawei, Cyfronet and Divia; IBM; and RHEA Group, T-Systems, Exoscale and SixSq. Each presented its plans to build the HNSciCloud prototype and the first deliverables are expected by the end of the year, after which two consortia will proceed to the pilot phase in 2018. The CERN Accelerator School (CAS) organised a specialised course devoted to beam injection, extraction and transfer in Erice, Sicily, from 10 to 19 March. The course was held in the Ettore Majorana Foundation and Centre, and was attended by 72 participants from 25 countries including China, Iran, Russia and the US. The intensive programme comprised 32 lectures and two seminars, with 10 hours of case studies allowing students to apply their knowledge to real problems. Following introductory talks on electromagnetism, relativity and the basics of beam dynamics, different injection and extraction schemes were presented. Detailed lectures about the special magnetic and electrostatic elements for the case of lepton and hadron beams followed. State-of-the-art kicker and septa designs were discussed, as were issues related to stripping-injection and resonant extraction as used in medical settings. An overview of optics measurements in storage rings and non-periodic structures completed the programme, with talks about the production of secondary and radioactive beams and exotic injection methods. The next CAS course, focusing on advanced accelerator physics, will take place at Royal Holloway University in the UK from 3–15 September. Later in the year, CAS is participating in a joint venture in collaboration with the accelerator schools of the US, Japan and Russia. This school is devoted to RF technologies and will be held in Japan from 16–26 October. Looking further ahead, schools are currently planned in 2018 on accelerator physics at the introductory level, on future colliders and on beam instrumentation and diagnostics. See https://www.cern.ch/schools/CAS. Around 100 participants from 15 countries attended the 2017 Testing Gravity Conference at the Simon Fraser University, Harbour Centre, in Vancouver, Canada, on 25 to 28 January. The conference, the second such meeting following the success of the 2015 event, brought together experts exploring new ways to test general relativity (GR). GR, and its Newtonian limit, work very well in most circumstances. But gaps in our understanding appear when the theory is applied to extremely small distances, where quantum mechanics reigns, or extremely large distances, when we try to describe the universe. Advancing technologies across all areas of physics open up opportunities for testing gravity in new ways, thus helping to fill these gaps. The conference brought together renowned cosmologists, astrophysicists, and atomic, nuclear and particle physicists to share their specific approaches to test GR and to explore ways to address long-standing mysteries, such as the unexplained nature of dark matter and dark energy. Among the actively discussed topics were the breakthrough discovery in February 2016 of gravitational waves by the LIGO observatory, which has opened up exciting opportunities for testing GR in detail (CERN Courier January/February 2017 p34), and the growing interest in gravity tests among the CERN physics community – specifically regarding attempting to measure the gravitational force on antihydrogen with three experiments at CERN’s Antiproton Decelerator (CERN Courier January/February 2017 p39). Among other highlights there were fascinating talks from pioneers in their fields, including cosmologist Misao Sasaki, one of the fathers of inflationary theory; Eric Adelberger, a leader in gravity tests at short distances; and Frans Pretorius, who created the first successful computer simulations of black-hole collisions. This is an exciting time for the field of gravity research. The LIGO–Virgo collaboration is expected to detect many more gravitational-wave events from binary black holes and neutron stars. Meanwhile, a new generation of cosmological probes currently under development, such as Euclid, LSST and SKA, are stimulating theoretical research in their respective domains (CERN Courier May 2017 p19). We are already looking forward to the next Testing Gravity in Vancouver in 2019. On 12 April, CERN hosted the seven-member high-level group of scientific advisers to the European Commission, which provides independent scientific advice on specific policy issues. Led by former CERN Director-General Rolf Heuer, the group toured ATLAS and the AMS Payload Operations Control Centre. On 18 April, Czech minister of health Miloslav Ludvik visited CERN, during which he toured the ALICE experiment and signed the guestbook with head of Member State relations Pippa Wells. Minister for higher education and science in Denmark Søren Pind visited CERN on 25 April, touring the synchrocyclotron, the Antiproton Decelerator, ALICE and ATLAS. Here he is pictured (centre) meeting ATLAS spokesperson Karl Jakobs. Dr Viktoras Pranckietis MP and speaker of the Seimas, Republic of Lithuania, visited CERN on 26 April, taking in CMS, ISOLDE and MEDICIS. He signed the guestbook with senior adviser for Lithuania Tadeusz Kurtyka (left) and director for finance and human resources Martin Steinacher.
News Article | April 20, 2017
When the fuel of a very massive star is spent, it collapses due to its own gravitational pull and eventually becomes a very small region of arbitrarily high matter density, that is a 'Singularity', where the usual laws of physics may breakdown. If this singularity is hidden within an event horizon, which is an invisible closed surface from which nothing, not even light, can escape, then we call this object a black hole. In such a case, we cannot see the singularity and we do not need to bother about its effects. But what if the event horizon does not form? In fact, Einstein's theory of general relativity does predict such a possibility when massive stars collapse at the end of their life-cycles. In this case, we are left with the tantalizing option of observing a naked singularity. An important question then is, how to observationally distinguish a naked singularity from a black hole. Einstein's theory predicts an interesting effect: the fabric of spacetime in the vicinity of any rotating object gets 'twisted' due to this rotation. This effect causes a gyroscope spin and makes orbits of particles around these astrophysical objects precess. The TIFR team has recently argued that the rate at which a gyroscope precesses (the precession frequency), when placed around a rotating black hole or a naked singularity, could be used to identify this rotating object. Here is a simple way to describe their results. If an astronaut records a gyroscope's precession frequency at two fixed points close to the rotating object, then two possibilities can be seen: (1) the precession frequency of the gyroscope changes by an arbitrarily large amount, that is, there is a wild change in the behaviour of the gyroscope; and (2) the precession frequency changes by a small amount, in a regular well-behaved manner. For the case (1), the rotating object is a black hole, while for the case (2), it is a naked singularity. The TIFR team, namely, Dr. Chandrachur Chakraborty, Mr. Prashant Kocherlakota, Prof. Sudip Bhattacharyya and Prof. Pankaj Joshi, in collaboration with a Polish team comprising Dr. Mandar Patil and Prof. Andrzej Krolak, has in fact shown that the precession frequency of a gyroscope orbiting a black hole or a naked singularity is sensitive to the presence of an event horizon. A gyroscope circling and approaching the event horizon of a black hole from any direction behaves increasingly 'wildly,' that is, it precesses increasingly faster, without a bound. But, in the case of a naked singularity, the precession frequency becomes arbitrarily large only in the equatorial plane, but being regular in all other planes. The TIFR team has also found that the precession of orbits of matter falling into a rotating black hole or a naked singularity can be used to distinguish these exotic objects. This is because the orbital plane precession frequency increases as the matter approaches a rotating black hole, but this frequency can decrease and even become zero for a rotating naked singularity. This finding could be used to distinguish a naked singularity from a black hole in reality, because the precession frequencies could be measured in X-ray wavelengths, as the infalling matter radiates X-rays. Explore further: How fast do black holes spin? More information: Chandrachur Chakraborty et al, Spin precession in a black hole and naked singularity spacetimes, Physical Review D (2017). DOI: 10.1103/PhysRevD.95.044006 Chandrachur Chakraborty et al. Distinguishing Kerr naked singularities and black holes using the spin precession of a test gyro in strong gravitational fields, Physical Review D (2017). DOI: 10.1103/PhysRevD.95.084024
News Article | February 15, 2017
Tom Dombeck, an innovative and versatile physicist and project manager, passed away in Kāneʻohe, Hawaii, on 4 November 2016. His legacy includes many measurements in particle physics, the development of new techniques for the production of ultra-cold neutrons and substantial contributions to the management of several major scientific projects. Tom received a BA in physics from Columbia University in 1967 and a PhD in particle physics from Northwestern University in 1972, and his career saw him hold prominent roles at numerous institutes. He was a research associate at Imperial College London from 1972 to 1974 and visiting scientist at Dubna in the former USSR in 1975. Following six years at the University of Maryland, from 1981 to 1988 Tom held various roles at Los Alamos National Laboratory (LANL) after which he spent a year working in the US Department of Energy in the office of the Superconducting Supercollider (SSC). Afterwards he became a staff physicist and ultimately deputy project manager for operations at the SSC laboratory in Texas, where he led the successful “string test”. In 1994 he moved to a role as project manager for the Sloan Digital Sky Survey at the University of Chicago. Tom was deputy head for the technical division at Fermilab from 1997 to 1999, and project manager for the Next Linear Collider project at Fermilab between 2000 and 2002. From 2003 to 2006 he was project manager for the Pan-STARRS telescope at the University of Hawaii and an affiliated graduate faculty member there until 2016. Tom began his scientific research with bubble chambers and was a key participant in the experiment that observed the first neutrino interaction in a hydrogen filled bubble chamber in 1970 at the ZGS at Argonne National Laboratory. For many years he pursued measurements of the electric dipole moment (EDM) of the neutron and was also involved in the development of ultra-cold neutrons by Doppler shifting at pulsed sources. He proposed a new method for a neutron EDM measurement that involved Bragg scattering polarised neutrons from a silicon crystal and led an initial effort at the Missouri University Research Reactor, after which he initiated an experiment using the reactor at the NIST Center for Neutron Research. While at LANL, Tom led a neutrino-oscillation search that involved constructing a new beamline and neutrino source at LAMPF and provided improved limits on muon-neutrino to electron-neutrino oscillations. He carried these fundamental physics interests and abilities to his later work as a highly effective scientific programme manager. Tom was able to see the connections between disparate scientific areas and bring together new ideas and approaches that moved the field forwards. He could inspire people around him with his enthusiasm and kindness, and his wry sense of humour and wicked smile were trademarks that will long be remembered by his friends and colleagues. Tom was a devoted family man and is missed greatly by his wife Bonnie, his two children, Daniel and Heidi, and his four grandchildren. Sidney David Drell, professor emeritus of theoretical physics at SLAC National Accelerator Laboratory, senior fellow at Stanford’s Hoover Institution and a giant in the worlds of both academia and policy, died on 21 December 2016 at his home in Palo Alto, California. He was 90 years old. Drell made immense contributions to his field, including uncovering a process that bears his name and working on national and international security. His legacy as a humanitarian includes his friendship and support of Soviet physicist and dissident Andrei Sakharov, who won the Nobel Peace Prize in 1975 for his opposition of the abuse of power in the Soviet Union. Drell was also known for his welcoming nature and genuine, albeit perhaps unwarranted, humility. Drell’s commitment to arms control spanned more than 50 years. He served on numerous panels advising US Congress, the intelligence community and military. He was an original member of JASON, a group of academic scientists created to advise the government on national security and defence issues, and from 1992 to 2001 he was a member of the President’s Foreign Intelligence Advisory Board. He was also the co-founder of the Center for International Security and Cooperation at Stanford, and in 2006 he and former Secretary of State George Shultz began a programme at the Hoover Institution dedicated to developing practical steps towards ridding the world of nuclear weapons. In 1974, Drell met Sakharov at a conference hosted by the Soviet Academy of Sciences and they quickly became friends. When Sakharov was internally exiled to Gorky from 1980 to 1986 following his criticism of the Soviet invasion of Afghanistan, Drell exchanged letters with him and called on Soviet leader Mikhail Gorbachev for his release. He also organised a petition to allow another Soviet physicist and dissident, Nohim Meiman, to emigrate to Israel, and obtained the signatures of 118 members of the US National Academy of Sciences. Having graduated with a bachelor’s degree from Princeton University in 1946, Drell earned a master’s degree in 1947 and a PhD in physics in 1949 from the University of Illinois, Urbana-Champaign. He began at Stanford in 1950 as an instructor in physics, leaving to work as a researcher and assistant professor at the Massachusetts Institute of Technology and then returning to Stanford in 1956 as a professor of physics. He served as deputy director of SLAC from 1969 until his retirement from the lab in 1998. Drell’s research was in the fields of quantum electrodynamics and quantum chromodynamics. While at SLAC, he and research associate Tung-Mow Yan formulated the famous Drell–Yan Process, which has become an invaluable tool in particle physics. His theoretical work was critical in setting SLAC on the course that it took. As head of the SLAC theory group, Drell brought in a host of younger theoretical physicists who began creating the current picture of the structure of matter. He played an important role in developing the justification for experiments and turning the results into what became the foundation of the Standard Model of particle physics. For his research and lifetime of service to his country, Drell received many prestigious awards, including: the National Medal of Science; the Enrico Fermi Award; a fellowship from the MacArthur Foundation; the Heinz Award for contributions in public policy; the Rumford Medal from the American Academy of Arts and Sciences; and the National Intelligence Distinguished Service Medal. Drell was one of 10 scientists honoured as the founders of satellite reconnaissance as a space discipline by the US National Reconnaissance Office. He was elected to the National Academy of Sciences, the American Academy of Arts and Sciences and the American Philosophical Society, and was president of the American Physical Society in 1986. Drell was also an accomplished violinist who played chamber music throughout his life. He is survived by his wife, Harriet, and his children, Daniel, Virginia, Persis and Joanna. Persis Drell, a former director of SLAC who is also a physicist at Stanford and dean of the School of Engineering, will be the university’s next provost. • Based, with permission, on the obituary published on the Stanford University website on 22 December 2016. Mambillikalathil Govind Kumar Menon, a pioneer in particle physics and a distinguished statesman of science, passed away peacefully on 22 November at his home in New Delhi, India. He graduated with a bachelor of science from Jaswant College, Jodhpur, in 1946, and inspired by Chandrasekhara Venkata Raman, studied under the tutelage of spectroscopist Nanasaheb R Tawde before joining Cecil Powell’s group at the University of Bristol, UK, in 1949. Menon’s first important contribution was to establish the bosonic character of the pion through a study of fragments emerging from π-capture by light nuclei. He then focused his attention on the emerging field of K-meson physics. Along with his colleagues at Bristol, notably Peter Fowler, Cecil Powell and Cormac O’Ceallaigh, Menon discovered K+ → π+ π0 and K+ → π+ π– π+ events in nuclear emulsion indicating parity non-conservation, (the τ – θ puzzle). He also identified a sizeable collection of events showing the associated production of kaons and hyperons. In 1955 Menon joined the Tata Institute of Fundamental Research (TIFR), where he worked on cosmic-ray research programmes initiated by Homi Bhabha. Following Bhabha’s death in an air crash over Mont Blanc in 1966, the responsibility of the directorship of TIFR fell squarely on his shoulders, along with the wide-ranging initiatives for national development that Bhabha had started. Notwithstanding these additional demands on his time, his focus on particle physics never wavered. He continued with his research, establishing a collaboration with Arnold W Wolfendale at the University of Durham, UK, and Saburo Miyake of Osaka City University, Japan, for the study of particle physics with detectors deployed deep underground; he detected events induced by cosmic-ray neutrino interactions; and he also launched a dedicated effort to test the early predictions of violation of baryon-number conservation leading to proton decay. During his Bristol years, Menon established a close friendship with William O Lock, who had moved to CERN in 1959. This facilitated collaboration between TIFR and CERN, leading to the development of bubble-chamber techniques to study mesons produced in proton–antiproton collisions. These initial studies eventually led to highly successful collaborations between Indian researchers and the L3 experiment at LEP, and the CMS, ALICE and ATLAS experiments at the LHC. Menon won several awards including the Cecil F Powell and C V Raman medals, and was elected to the three scientific academies in India. He was elected as a fellow of the Royal Society in 1970, and subsequently to the Pontifical Academy of Sciences, American Academy of Arts and Sciences, the Russian Academy of Sciences and as an honorary fellow of the Institute of Physics and the Institution of Electrical & Electronics Engineers. He also served two terms as president of the International Council of Scientific Unions, and stimulated its participation in policy issues, including climate change. Menon held a firm conviction that science can bring about technological development and societal progress, which motivated him to work with Abdus Salam in founding the Third World Academy of Sciences. He held several high positions in the Indian government, and thus contributed to the growth of science and technology in India. Alongside his scientific achievements, M G K Menon was also very close to his wife Indumati and their two children Preeti and Anant Kumar. Our warmest thoughts go out to them and to innumerable others whose lives he touched in so many important ways. Helmut Oeschler, an active member of the ALICE collaboration, passed away from heart failure on 3 January while working at his desk. Born in Southern Germany, he received his PhD from the University of Heidelberg in 1972 and held postdoc positions at the Niels Bohr Institute in Copenhagen, and in Strasbourg, Saclay and Orsay in France. From 1981 he was at the Institute for Nuclear Physics of TU Darmstadt. He held a Doctorate Honoris Causa from Dubna University, Russia, and in 2006 he received the Gay-Lussac-Humboldt prize. Oeschler’s physics interests concerned the dynamics of nuclear reactions over a broad energy range, from the Coulomb barrier to ultra-relativistic collisions. He was a driving force for building the kaon spectrometer at the GSI in Darmstadt, which made it possible to measure strange particles in collisions of heavy nuclei. From the late 1990s he was actively involved in addressing new aspects of equilibration in relativistic nuclear reactions. Oeschler became a member of the ALICE collaboration at CERN in 2000 and made important contributions to the construction of the experiment. Together with his students, he was involved in developing track reconstruction software for measuring the production of charged particles in lead–lead collisions at the LHC. He also led the analysis efforts for the measurements of identified charged hadrons in the LHC’s first proton–proton collisions. From 2010 to 2014 he led the ALICE editorial board, overseeing the publication of key results relating to quark-gluon matter at the highest energy densities. His deep involvement in the data analysis and interpretation continued unabated and he made important contributions to several research topics. Advising and working in close collaboration with students was a much loved component of Helmut’s activity and was highly appreciated among the ALICE collaboration. Helmut Oeschler was a frequent visitor of South Africa and served there on numerous international advisory committees. He was instrumental in helping the South African community develop the physics of heavy-ion collisions and collaboration with CERN. With Helmut Oeschler we have lost an internationally renowned scientist and particular friend and colleague. His scientific contributions, especially on the production of strange particles in high-energy collisions, are important achievements.
News Article | December 14, 2016
Professor Sudip Bhattacharyya of the Tata Institute of Fundamental Research (TIFR), Mumbai, India, and Professor Deepto Chakrabarty (MIT, USA), an adjunct visiting professor at the same institute, have shown that a population of neutron stars should spin around their axes much faster than the highest observed spin rate of any neutron star. They pointed out that the observed lower spin rates are possible if these neutron stars emit gravitational waves continuously, and hence spin down. Neutron stars are the densest observable objects in the universe, with a fistful of stellar material outweighing a mountain on Earth. While such stars are not bigger than a city, in size, they have more material than in the Sun crammed inside them. A population of these stars can increase their spin rate by the transfer of matter from a normal companion star. Infact, some of them have been observed to spin several hundred times in a second around their own axes. In the 1970s, it was theoretically worked out how fast these neutron stars could spin, and since then this has formed the basis of studies of these stars. But the new study led by Professor Bhattacharyya has shown that for episodic mass transfer, which happens for many neutron stars, the stellar spin rate should be much higher, and the star could easily attain a spin rate more than a thousand times per second. Since no neutron star has been observed with such a high spin rate, the team has pointed out that many of these stars are likely to be slowed down by continuously emitting gravitational waves. Gravitational waves emitted by massive objects is a prediction of Einstein's general theory of relativity, which has recently been discovered during transient phenomena of black hole mergers. But the detection of continuous gravitational waves, which could provide an opportunity to study these waves almost permanently, is still elusive. The new study of Professors Bhattacharyya and Chakrabarty provide a strong indication that many fast spinning neutron stars generate gravitational waves continuously, and careful observations should be made to detect such waves.
News Article | March 2, 2017
Nanotechnology - What You Should Know Graphene - Here's What You Should Know Super material graphene's properties are multifarious. It has strong chemical stability, high conductivity, and super strength. However, magnetic properties have been a sore point with many skeptics lowering expectations on graphene as a replacement for silicon in future microprocessors. In a new study, researchers at the Tata Institute of Fundamental Research in India evolved a new type of magnet that optimizes the magnetism of electrons in three-layered graphene at a temperature as low as -272 Celsius. The study, published in Nature Communications, explains how coordinated whispers between electrons are achieving that ferromagnetism. Unlike metals, the density of electrons in graphene is too low as it is just one atom thick. That is why illustrating the wave nature of electrons under quantum mechanics with graphene is easy. That property will be better understood when graphene is contrasted with a metal like copper whose electrons might be scattered every 100 nanometers because of impurities. In sharp contrast, electrons of graphene can travel greater distances up to 10 micrometers. In the TIFR experiments, this long-range travel of graphene electrons was achieved by sandwiching graphene with boron nitride layers, which are defect free and which refrain from blocking the electron flow. The ability of a material's electrons to travel great distances implies that there are no flaws and the electrons can conduct soft whispers just like "talking to each other." Reduced flaws are similar to the condition in a silent room where even a soft whisper becomes audible as there are few disturbances. This whisper of electrons and the resulting magnetism has been explained by doctoral student Biswajit Datta, working with the group of Professor Mandar Deshmukh at TIFR. The team understood that the silence is enabling enhanced electronic interactions in the three layers of graphene and leading to the formation of a new type of magnet with graphene. The insights explain how electronic devices can leverage graphene for scientific studies and applications. Already some researchers have offered solutions for making graphene magnetic by inserting hydrogen atoms into specific areas in the graphene lattice. Physicists from Spain and Egypt have suggested that when a group of electrons in nanoscale domains is encoded with the magnetic spin, they will transform graphene into a spintronic material capable of replacing silicon. If the experiment succeeds, thanks to hydrogen's single electron property it will be the densest spintronic material ever detected. A magnetic graphene will have an astounding range of applications starting from information processing to advanced medicine. Magnetic graphene will be playing a big role in spintronics. In the spin transport electronics applications, signals will be processed by magnetic spins in place of electric charges. The technology offers faster processors and high memory. Miniaturization of silicon transistors is already hitting a plateau. New generation processors including those from Intel are down to 14nm with the 5nm size expected in 2020, marking the possible functional end of small sizes. Magnetic graphene in spintronics may go mainstream and take the place of traditional silicon transistors and work on the atomic scale. Meanwhile, South Australia's Flinders University and First Graphite Ltd company are aiming high-quality graphene production using Vortex Fluidic Device. Globally, graphite mining runs into millions of metric tons every year. According to Craig McGuckin, managing director of First Graphite, graphene will be indispensable in a vast number of industries and the demand will be high. "What is required is creating high-quality graphene from graphite, doing so quickly and efficiently and that is what we are trying to take up now," he said. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | November 3, 2016
The GRAPES-3 muon telescope located at TIFR's Cosmic Ray Laboratory in Ooty recorded a burst of galactic cosmic rays of about 20 GeV, on 22 June 2015 lasting for two hours. The burst occurred when a giant cloud of plasma ejected from the solar corona, and moving with a speed of about 2.5 million kilometers per hour struck our planet, causing a severe compression of Earth's magnetosphere from 11 to 4 times the radius of Earth. It triggered a severe geomagnetic storm that generated aurora borealis, and radio signal blackouts in many high latitude countries. Earth's magnetosphere extends over a radius of a million kilometers, which acts as the first line of defence, shielding us from the continuous flow of solar and galactic cosmic rays, thus protecting life on our planet from these high intensity energetic radiations. Numerical simulations performed by the GRAPES-3 collaboration on this event indicate that the Earth's magnetic shield temporarily cracked due to the occurrence of magnetic reconnection, allowing the lower energy galactic cosmic ray particles to enter our atmosphere. Earth's magnetic field bent these particles about 180 degree, from the day-side to the night-side of the Earth where it was detected as a burst by the GRAPES-3 muon telescope around mid-night on 22 June 2015. The data was analyzed and interpreted through extensive simulation over several weeks by using the 1280-core computing farm that was built in-house by the GRAPES-3 team of physicists and engineers at the Cosmic Ray Laboratory in Ooty. This work has recently been published in Physical Review Letters Solar storms can cause major disruption to human civilization by crippling large electrical power grids, global positioning systems (GPS), satellite operations and communications. The GRAPES-3 muon telescope, the largest and most sensitive cosmic ray monitor operating on Earth is playing a very significant role in the study of such events. This recent finding has generated widespread excitement in the international scientific community, as well as electronic and print media. Explore further: The magnetosphere has a large intake of solar wind energy More information: P. K. Mohanty et al, Transient Weakening of Earth's Magnetic Shield Probed by a Cosmic Ray Burst, Physical Review Letters (2016). DOI: 10.1103/PhysRevLett.117.171101