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CERN Courier–Digital Edition
CERNMarch/April 2021 cerncourier.com COURIERReporting on international high-energy physics WELCOME CERN Courier – digital edition Welcome to the digital edition of the March/April 2021 issue of CERN Courier. Hadron colliders have contributed to a golden era of discovery in high-energy physics, hosting experiments that have enabled physicists to unearth the cornerstones of the Standard Model. This success story began 50 years ago with CERN’s Intersecting Storage Rings (featured on the cover of this issue) and culminated in the Large Hadron Collider (p38) – which has spawned thousands of papers in its first 10 years of operations alone (p47). It also bodes well for a potential future circular collider at CERN operating at a centre-of-mass energy of at least 100 TeV, a feasibility study for which is now in full swing. Even hadron colliders have their limits, however. To explore possible new physics at the highest energy scales, physicists are mounting a series of experiments to search for very weakly interacting “slim” particles that arise from extensions in the Standard Model (p25). Also celebrating a golden anniversary this year is the Institute for Nuclear Research in Moscow (p33), while, elsewhere in this issue: quantum sensors HADRON COLLIDERS target gravitational waves (p10); X-rays go behind the scenes of supernova 50 years of discovery 1987A (p12); a high-performance computing collaboration forms to handle the big-physics data onslaught (p22); Steven Weinberg talks about his latest work (p51); and much more. To sign up to the new-issue alert, please visit: http://comms.iop.org/k/iop/cerncourier To subscribe to the magazine, please visit: https://cerncourier.com/p/about-cern-courier EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING ATLAS spots rare Higgs decay Weinberg on effective field theory Hunting for WISPs CCMarApr21_Cover_v1.indd 1 12/02/2021 09:24 CERNCOURIER www. -
LHC Explore Pentaquark
LHC Explore Pentaquark Scientists at the Large Hadron Collider have announced the discovery of a new particle called the pentaquark. [9] CERN scientists just completed one of the most exciting upgrades on the Large Hadron Collider—the Di-Jet Calorimeter (DCal). [8] As physicists were testing the repairs of LHC by zipping a few spare protons around the 17 mile loop, the CMS detector picked up something unusual. The team feverishly pored over the data, and ultimately came to an unlikely conclusion—in their tests, they had accidentally created a rainbow universe. [7] The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein's theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once. [6] This paper explains the Accelerating Universe, the Special and General Relativity from the observed effects of the accelerating electrons, causing naturally the experienced changes of the electric field potential along the moving electric charges. The accelerating electrons explain not only the Maxwell Equations and the Special Relativity, but the Heisenberg Uncertainty Relation, the wave particle duality and the electron’s spin also, building the bridge between the Classical and Relativistic Quantum Theories. The Big Bang caused acceleration created the radial currents of the matter and since the matter composed of negative and positive charges, these currents are creating magnetic field and attracting forces between the parallel moving electric currents. This is the gravitational force experienced by the matter, and also the mass is result of the electromagnetic forces between the charged particles. -
Pentaquark Search Shows How Science Moves Forward
Although initial results were encouraging, physicists searching for an exotic five-quark particle now think it probably doesn’t exist. The debate over the pentaquark search shows how science moves forward. The rise and fall of the PE NTAQUAR K by Kandice Carter, Jefferson Lab 16 Three years ago, research teams around the stars are made. Yet he and his peers had no world announced they had found data hinting at means to verify its existence. the existence of an exotic particle containing Luminaries of 16th-19th century physics, five quarks, more than ever observed in any other including Newton, Fresnel, Stokes, and Maxwell, quark-composite particle. More than two dozen debated at length the properties of their physi- experiments have since taken aim at the particle, cal version of the philosophical concept, which dubbed the pentaquark, and its possible partners, they called ether. in the quest to turn a hint into a discovery. It’s a The ether was a way to explain how light scenario that often plays out in science: an early could travel through empty space. In 1881, theory or observation points to a potentially Albert A. Michelson began to explore the ether important discovery, and experimenters race to concept with experimental tools. But his first corroborate or to refute the idea. experiments, which seemed to rule out the “Research is the process of going up alleys to existence of the ether, were later realized to be see if they are blind,” said Marston Bates, a zool- inconclusive. ogist whose research on mosquitoes led to Six years later, Michelson paired up with an understanding of how yellow fever is spread. -
Stephen Hawking (1942–2018) World-Renowned Physicist Who Defied the Odds
COMMENT OBITUARY Stephen Hawking (1942–2018) World-renowned physicist who defied the odds. hen Stephen Hawking was speech synthesizer processed his words and diagnosed with motor-neuron generated the androidal accent that became disease at the age of 21, it wasn’t his trademark. In this way, he completed his Wclear that he would finish his PhD. Against best-selling book A Brief History of Time all expectations, he lived on for 55 years, (Bantam, 1988), which propelled him to becoming one of the world’s most celebrated celebrity status. IAN BERRY/MAGNUM scientists. Had Hawking achieved equal distinction Hawking, who died on 14 March 2018, was in any other branch of science besides cos- born in Oxford, UK, in 1942 to a medical- mology, it probably would not have had the researcher father and a philosophy-graduate same resonance with a worldwide public. As mother. After attending St Albans School I put it in The Telegraph newspaper in 2007, near London, he earned a first-class degree “the concept of an imprisoned mind roaming in physics from the University of Oxford. He the cosmos” grabbed people’s imagination. began his research career in 1962, enrolling In 1965, Stephen married Jane Wilde. as a graduate student in a group at the Uni- After 25 years of marriage, and three versity of Cambridge led by one of the fathers children, the strain of Stephen’s illness of modern cosmology, Dennis Sciama. and of sharing their home with a team of The general theory of relativity was at that nurses became too much and they sepa- time undergoing a renaissance, initiated in rated, divorcing in 1995. -
CERN Celebrates Discoveries
INTERNATIONAL JOURNAL OF HIGH-ENERGY PHYSICS CERN COURIER VOLUME 43 NUMBER 10 DECEMBER 2003 CERN celebrates discoveries NEW PARTICLES NETWORKS SPAIN Protons make pentaquarks p5 Measuring the digital divide pl7 Particle physics thrives p30 16 KPH impact 113 KPH impact series VISyN High Voltage Power Supplies When the objective is to measure the almost immeasurable, the VISyN-Series is the detector power supply of choice. These multi-output, card based high voltage power supplies are stable, predictable, and versatile. VISyN is now manufactured by Universal High Voltage, a world leader in high voltage power supplies, whose products are in use in every national laboratory. For worldwide sales and service, contact the VISyN product group at Universal High Voltage. Universal High Voltage Your High Voltage Power Partner 57 Commerce Drive, Brookfield CT 06804 USA « (203) 740-8555 • Fax (203) 740-9555 www.universalhv.com Covering current developments in high- energy physics and related fields worldwide CERN Courier (ISSN 0304-288X) is distributed to member state governments, institutes and laboratories affiliated with CERN, and to their personnel. It is published monthly, except for January and August, in English and French editions. The views expressed are CERN not necessarily those of the CERN management. Editor Christine Sutton CERN, 1211 Geneva 23, Switzerland E-mail: [email protected] Fax:+41 (22) 782 1906 Web: cerncourier.com COURIER Advisory Board R Landua (Chairman), P Sphicas, K Potter, E Lillest0l, C Detraz, H Hoffmann, R Bailey -
Subnuclear Physics: Past, Present and Future
Subnuclear Physics: Past, Present and Future International Symposium 30 October - 2 November 2011 – The purpose of the Symposium is to discuss the origin, the status and the future of the new frontier of Physics, the Subnuclear World, whose first two hints were discovered in the middle of the last century: the so-called “Strange Particles” and the “Resonance #++”. It took more than two decades to understand the real meaning of these two great discoveries: the existence of the Subnuclear World with regularities, spontaneously plus directly broken Symmetries, and totally unexpected phenomena including the existence of a new fundamental force of Nature, called Quantum ChromoDynamics. In order to reach this new frontier of our knowledge, new Laboratories were established all over the world, in Europe, in USA and in the former Soviet Union, with thousands of physicists, engineers and specialists in the most advanced technologies, engaged in the implementation of new experiments of ever increasing complexity. At present the most advanced Laboratory in the world is CERN where experiments are being performed with the Large Hadron Collider (LHC), the most powerful collider in the world, which is able to reach the highest energies possible in this satellite of the Sun, called Earth. Understanding the laws governing the Space-time intervals in the range of 10-17 cm and 10-23 sec will allow our form of living matter endowed with Reason to open new horizons in our knowledge. Antonino Zichichi Participants Prof. Werner Arber H.E. Msgr. Marcelo Sánchez Sorondo Prof. Guido Altarelli Prof. Ignatios Antoniadis Prof. Robert Aymar Prof. Rinaldo Baldini Ferroli Prof. -
People and Things
Physics monitor People and things Books received CERN Council Bookshelf At the meeting of CERN's governing Future High Energy Colliders, Editor body, Council, in December, Luciano Weak Neutral Currents - The Zohreh Parsa, AIP Conference Maiani was elected the next Director Discovery of the Electro-Weak Force, Proceedings 397, ISBN 1-56396- General of the Organization, to take edited by David B. Cline, Addison 729-4 office on 1 January 1999, when the Wesley (Frontiers of Physics Series), current Director General, Chris ISBN 0-201-93347-0 Llewellyn Smith, will have completed Proceedings of a meeting held in his five year mandate. A Addison Wesley's Frontiers of Santa Barbara in October 1996 (see distinguished theorist, Luciano Physics Series began in 1961, and March 1997 issue of the CERN Maiani is currently President of the David Cline's anthology on weak Courier, page 16). Italian INFN and has been President neutral currents is the 97th volume in of CERN Council since January the series. 'Frontiers' books usually 1997. make extensive use of lecture notes The Interpretation of Quantum At the same meeting, leading or reprints, and Cline's volume takes Mechanics and the Measurement German science administrator and the latter route. It is divided into 9 Process, by Peter Mittelstaedt, head of Germany's CERN delegation chapters: The Weak Interaction Cambridge University Press 0 521 Hans C. Eschelbacher was elected Uncovered; Forty Years of Weak 55445 4 £30/$44.95 President of CERN Council for an Interactions; The Search for Other initial period of one year from 1 Forms of Weak Interaction; The January 1998, replacing Luciano Electroweak Interaction Picture A volume of interest to the more Maiani. -
CERN to Seek Answers to Such Fundamental 1957, Was CERN’S First Accelerator
What is the nature of our universe? What is it ----------------------------------------- DAY 1 -------- made of? Scientists from around the world go to The 600 MeV Synchrocyclotron (SC), built in CERN to seek answers to such fundamental 1957, was CERN’s first accelerator. It provided questions using particle accelerators and pushing beams for CERN’s first experiments in particle and nuclear the limits of technology. physics. In 1964, this machine started to concentrate on nuclear physics alone, leaving particle physics to the newer During February 2019, I was given a once in a lifetime and more powerful Proton Synchrotron. opportunity to be part of The Maltese Teacher Programme at CERN, which introduced me, as one of the participants, to cutting-edge particle physics through lectures, on-site visits, exhibitions, and hands-on workshops. Why do they do all this? The main objective of these type of visits is to bring modern science into the classroom. Through this report, my purpose is to give an insight of what goes on at CERN as well as share my experience with you students, colleagues, as well as the general public. The SC became a remarkably long-lived machine. In 1967, it started supplying beams for a dedicated radioactive-ion-beam facility called ISOLDE, which still carries out research ranging from pure What does “CERN” stand for? At an nuclear physics to astrophysics and medical physics. In 1990, intergovernmental meeting of UNESCO in Paris in ISOLDE was transferred to the Proton Synchrotron Booster, and the SC closed down after 33 years of service. December 1951, the first resolution concerning the establishment of a European Council for Nuclear Research SM18 is CERN’s main facility for testing large and heavy (in French Conseil Européen pour la Recherche Nucléaire) superconducting magnets at liquid helium temperatures. -
Slides Lecture 1
Advanced Topics in Particle Physics Probing the High Energy Frontier at the LHC Ulrich Husemann, Klaus Reygers, Ulrich Uwer University of Heidelberg Winter Semester 2009/2010 CERN = European Laboratory for Partice Physics the world’s largest particle physics laboratory, founded 1954 Historic name: “Conseil Européen pour la Recherche Nucléaire” Lake Geneva Proton-proton2500 employees, collider almost 10000 guest scientists from 85 nations Jura Mountains 8.5 km Accelerator complex Prévessin site (approx. 100 m underground) (France) Meyrin site (Switzerland) Probing the High Energy Frontier at the LHC, U Heidelberg, Winter Semester 09/10, Lecture 1 2 Large Hadron Collider: CMS Experiment: Proton-Proton and Multi Purpose Detector Lead-Lead Collisions LHCb Experiment: B Physics and CP Violation ALICE-Experiment: ATLAS Experiment: Heavy Ion Physics Multi Purpose Detector Probing the High Energy Frontier at the LHC, U Heidelberg, Winter Semester 09/10, Lecture 1 3 The Lecture “Probing the High Energy Frontier at the LHC” Large Hadron Collider (LHC) at CERN: premier address in experimental particle physics for the next 10+ years LHC restart this fall: first beam scheduled for mid-November LHC and Heidelberg Experimental groups from Heidelberg participate in three out of four large LHC experiments (ALICE, ATLAS, LHCb) Theory groups working on LHC physics → Cornerstone of physics research in Heidelberg → Lots of exciting opportunities for young people Probing the High Energy Frontier at the LHC, U Heidelberg, Winter Semester 09/10, Lecture 1 4 Scope -
Cusp Effects in Meson Decays
EPJ Web of Conferences 3, 01008 (2010) DOI:10.1051/epjconf/20100301008 © Owned by the authors, published by EDP Sciences, 2010 Cusp effects in meson decays Bastian Kubis,a Helmholtz-Institut f¨ur Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universit¨at Bonn, D-53115 Bonn, Germany Abstract. The pion mass difference generates a pronounced cusp in the π0π0 invariant mass distribution of K+ π0π0π+ decays. As originally pointed out by Cabibbo, an accurate measurement of the cusp may allow one to pin→ down the S-wave pion–pion scattering lengths to high precision. We present the non-relativistic effective field theory framework that permits to determine the structure of this cusp in a straightforward manner, including the effects of radiative corrections. Applications of the same formalism to other decay channels, in particular η and η′ decays, are also discussed. 1 The pion mass and pion–pion scattering alternative scenario of chiral symmetry breaking under the name of generalized chiral perturbation theory [4]. The approximate chiral symmetry of the strong interac- Fortunately, chiral low-energy constants tend to appear tions severely constrains the properties and interactions in more than one observable,and indeed, ℓ¯3 also features in of the lightest hadronic degrees of freedom, the would-be the next-to-leading-order corrections to the isospin I = 0 0 Goldstone bosons (in the chiral limit of vanishing quark S-wave pion–pion scattering length a0 [2], masses) of spontaneous chiral symmetry breaking that can be identified with the pions. The effective field theory that 7M2 0 = π + ǫ + 4 , a0 2 1 (Mπ) systematically exploits all the consequencesthat can be de- 32πFπ O rived from symmetries is chiral perturbation theory [1,2], 5M2 n 3 o 21 21 which provides an expansion of low-energy observables in = π ¯ + ¯ ¯ + ¯ + ǫ 2 2 ℓ1 2ℓ2 ℓ3 ℓ4 . -
A Tribute to Bj0rn Wiik General Distribution: Jacques Dallemagne, CERN, 1211 Geneva 23, Switzerland
W M£W HSmzS OF THS p\J\Q fAMM WQ 722S: w PCI mmm FOR w - FOR. SUN, HP, b£C, MMs, Direct single shot and DMA transfers On-board PCI MMU On-board PCI chained DMA controller Generic C library and drivers for Windows NT, MacOS, SOLARIS, Digital UNIX, HPUX, LINUX PWC ?02S: Tf/e FUNCTION COMMWE zeptAcenem FOR W VIC ?2S0 / 22S7 VME transparent mapping in the PCI memory space VME transparent slot 1 and arbiter Full VME master / slave Support D&, D16, D32, D64, direct transfers On-board VME linked list DMA controller The CES-f3Pnet (CES backplane Driver Network) offers an efficient interprocessor communication and synchronization mechanism, combining microsecond-level resolution and network-oriented services over the PVIC. The CES-l3Pnet offers three types of services to ensure efficient communications between CES processors: • An extension of the POSIX inter processes communication (shared memory semaphores - message queues) • An efficient and straightforward message passing system • A full TCF/IF stack using the PVIC as a network device W CjPtO: fi USeZ-PZOQMMMm Q6N6RAL PUZPK6 f/WT / OlUM PHC Stepper motor Controller Timer and counter 32-bit Input / Outputs (TTL or DIFF) Multiple lines PS 455 / PS 232 / PS 422 . Up to 6 GPIOs connected on a single PI02 with PMC carrier boards extension SOFTWARE C\6F Programming Kit for FPGA equations LynxOS and VxWorks drivers for PI02 family CES Geneva, Switzerland Tel: +41-22 792 57 45 Fax: +41-22 792 57 4d EMail: ces^ces.ch CES.D Germany Tel: +49-60 51 96 97 4 ' Fax: +49-60 51 96 97 35 CE6 Creative Electronic Systems 5A, 70 Route du Pont-3utin, CH-1213 Petit-Lancy 1, Switzerland Internet: http://www.ces.ch CREATIVE ELECTRONIC SYSTEMS CONTENTS Covering current developments in high- energy physics and related fields worldwide CERN Courier is distributed to Member State governments, institutes and laboratories affiliated with CERN, and to their personnel. -
6.2 Transition Radiation
Contents I General introduction 9 1Preamble 11 2 Relevant publications 15 3 A first look at the formation length 21 4 Formation length 23 4.1Classicalformationlength..................... 24 4.1.1 A reduced wavelength distance from the electron to the photon ........................... 25 4.1.2 Ignorance of the exact location of emission . ....... 25 4.1.3 ‘Semi-bare’ electron . ................... 26 4.1.4 Field line picture of radiation . ............... 26 4.2Quantumformationlength..................... 28 II Interactions in amorphous targets 31 5 Bremsstrahlung 33 5.1Incoherentbremsstrahlung..................... 33 5.2Genericexperimentalsetup..................... 35 5.2.1 Detectors employed . ................... 35 5.3Expandedexperimentalsetup.................... 39 6 Landau-Pomeranchuk-Migdal (LPM) effect 47 6.1 Formation length and LPM effect.................. 48 6.2 Transition radiation . ....................... 52 6.3 Dielectric suppression - the Ter-Mikaelian effect.......... 54 6.4CERNLPMExperiment...................... 55 6.5Resultsanddiscussion....................... 55 3 4 CONTENTS 6.5.1 Determination of ELPM ................... 56 6.5.2 Suppression and possible compensation . ........ 59 7 Very thin targets 61 7.1Theory................................ 62 7.1.1 Multiple scattering dominated transition radiation . .... 62 7.2MSDTRExperiment........................ 63 7.3Results................................ 64 8 Ternovskii-Shul’ga-Fomin (TSF) effect 67 8.1Theory................................ 67 8.1.1 Logarithmic thickness dependence