Issue 10 Dimensions of Particle Physics Volume 04 a Joint Fermilab
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Very Forward Photon Production in Proton-Proton Collisions Measured by the Lhcf Experiment at the Large Hadron Collider
Very forward photon production in proton-proton collisions measured by the LHCf experiment at the Large Hadron Collider Author: Alessio Tiberio Supervisor: Lorenzo Bonechi The LHC-forward (LHCf) experiment, situated at the LHC accelerator, has measured neutral particles production in a very forward region (pseudo-rapidity η > 8:4) in proton-proton and proton- lead collisions. The main purpose of the LHCf experiment is to test hadronic interaction models used in ground based cosmic rays experiments to simulate cosmic rays induced air-showers in the Earth's atmosphere. Highest energy cosmic rays can only be detected from secondary particles which are produced by the interaction of the primary particle with nuclei of the atmosphere. Studying the development of air showers, it is possible to reconstruct the type and kinematic parameters of primary particle. For this reason, Monte Carlo (MC) simulations with accurate hadronic interaction models are needed to reproduce the development of air-showers. Since the energy flow of secondary particles is concentrated in the forward direction, measurements of particle production at high pseudo-rapidity (i.e. small angles) are very important. Furthermore, soft QCD interactions (non perturbative regime) dominates in the very forward region and MC simulations of air showers are based on phenomenological model, so inputs from experimental data are crucial. The experiment is composed by two independent detectors (Arm1 and Arm2 ) located at 140 m from the ATLAS's interaction point (IP1) on opposite sides [1]. Detectors are placed inside the Target Neutral Absorber (TAN), where the beam pipe from IP1 turns into two separates tubes: the position between the two beam pipes allows to measure particles produced at zero degrees. -
Spontaneous Electroweak Symmetry Breaking
Arianna Borrelli Who broke electroweak symmetry? Who broke electroweak symmetry? This question may sound rather naive, yet the discourse about the “spontaneous” breaking of electroweak symmetry entails a reference to agency which finds implicit expression in the often repeated (and equally often criticized) statement that the particles of the Standard Model “acquire” their mass “thanks to” the Higgs boson. The implicit agency manifests itself in its most extreme form in the nickname happily bestowed on the Higgs boson in the popular press: “the God particle”. The construction of spontaneous symmetry breaking can be analysed as the interplay between different mathematical formalisms, phenomena of various nature and verbal statements connecting the whole and endowing it with physical meaning. One may argue that the latter, verbal component played a key role in the development of the notion of spontaneous symmetry breaking, spinning a narrative which allowed to close gaps in mathematical arguments and downplay the arbitrariness of analogies between phenomena. From this process emerged an ambiguous mathematical-physical notion which was to become the symbolic carrier of a “mechanism of mass generation”. In the papers quoted as the origin of spontaneous symmetry breaking Yoshiro Nambu and Giovanni Jona Lasinio used an analogy to super-conductive systems to interpret the masses of strongly interacting particles as expression of an exact, but hidden symmetry (N 1960, N/JL 1961). They did not speak of “symmetry breaking” - let alone a “spontaneous” one - but rather of the existence of “superconductor solutions” to the equations for particle self-energy. Jeffrey Goldstone (1961) reformulated their arguments in terms of an elementary scalar field with non-zero vacuum expectation value, but it was Marshall Baker and Sheldon Glashow (1962) who framed the issue as “spontaneous symmetry breaking”, attempting to explain mass values in terms of “stable self-generated solution” of quantum-field-theoretical equations. -
Observation of Structure in the J/Ψ-Pair Mass Spectrum
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN) CERN-EP-2020-115 LHCb-PAPER-2020-011 November 10, 2020 Observation of structure in the J= -pair mass spectrum LHCb collaboration† Abstract p Using proton-proton collision data at centre-of-mass energies of s = 7, 8 and 13 TeV recorded by the LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 9 fb−1, the invariant mass spectrum of J= pairs is studied. A narrow structure around 6:9 GeV/c2 matching the lineshape of a resonance and a broad structure just above twice the J= mass are observed. The deviation of the data from nonresonant J= -pair production is above five standard deviations in the mass region between 6:2 and 7:4 GeV/c2, covering predicted masses of states composed of four charm quarks. The mass and natural width of the narrow X(6900) structure are measured assuming a Breit{Wigner lineshape. arXiv:2006.16957v2 [hep-ex] 10 Nov 2020 Keywords: QCD; exotics; tetraquark; spectroscopy; quarkonium; particle and resonance production Published in Science Bulletin 2020 65(23)1983-1993 © 2020 CERN for the benefit of the LHCb collaboration. CC BY 4.0 licence. †Authors are listed at the end of this paper. ii 1 Introduction The strong interaction is one of the fundamental forces of nature and it governs the dynamics of quarks and gluons. According to quantum chromodynamics (QCD), the theory describing the strong interaction, quarks are confined into hadrons, in agreement with experimental observations. The quark model [1,2] classifies hadrons into conventional mesons (qq) and baryons (qqq or qqq), and also allows for the existence of exotic hadrons such as tetraquarks (qqqq) and pentaquarks (qqqqq). -
From Leon Lederman, the God Particle (Last Reading Continued)
18 From Leon Lederman, The God Particle (last reading continued) …. DEMOCRITUS: I have trouble with emptiness. How do I describe it? If it is truly nothing, then how can it exist? My hands touch your desk here. On the way to the desk top, my palm feels the gentle rush of air that fills the void between me and the desk's surface. Yet air cannot be the void itself, as Empedocles so ably pointed out. How can I imagine my atoms if I cannot feel the void in which they must move? And yet, if I want to somehow account for the world by atoms, I must first define something that seems to be undefinable because it is devoid of properties. LEDERMAN: So what did you do? DEMOCRITUS [laughing]: I decided not to worry. I a-voided the issue. LEDERMAN: Oi Vay! DEMOCRITUS: Sorry. Seriously, I solved the problem with my knife. LEDERMAN: Your imaginary knife that cuts cheese into atoms? DEMOCRITUS: No, a real knife, cutting, say, a real apple. The blade must find empty places where it can penetrate. LEDERMAN: What if the apple is composed of solid atoms, packed together with no space? DEMOCRITUS: Then it would be impenetrable, because atoms are impenetrable. No, all matter that we can see and feel is cuttable if you have a sharp enough blade. Therefore the void exists. But mostly I said to myself back then, and I believe it still, that one must not forever be stalled by logical impasses. We go on, we continue as if nothingness can be accepted. -
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 -
Nfap Policy Brief » O C T O B E R 2017
NATIONAL FOUNDATION FOR AMERICAN POLICY NFAP POLICY BRIEF» O CTOBER 2017 IMMIGRANTS AND NOBEL PRIZES : 1901- 2017 EXECUTIVE SUMMARY Immigrants have been awarded 39 percent, or 33 of 85, of the Nobel Prizes won by Americans in Chemistry, Medicine and Physics since 2000. In 2017, the sole American winner of the Nobel Prize in Chemistry was an immigrant, Joachim Frank, a Columbia University professor born in Germany. Immigrant Reiner Weiss, who was born in Germany and came to the United States as a teenager, was awarded the 2017 Nobel Prize in Physics, sharing it with two other Americans, Kip S. Thorne and Barry C. Barish. In 2016, all 6 American winners of the Nobel Prize in economics and scientific fields were immigrants. These achievements by immigrants point to the gains to America of welcoming talent from across the globe. It does not mean America should welcome only Nobel Prize winners. Such a policy would be impossible to implement, since most immigrant Nobel Prize winners enter the United States many years before being awarded this honor. Most people immigrate to another country in their 20s, particularly employment-based immigrants, who either study in America or come here to work shortly after obtaining a degree abroad. The average of age of Nobel Prize winners at the time of the award is 59.5 years, according to economist Mark J. Perry.1 Table 1 Immigrant Nobel Prize Winners in Chemistry, Medicine and Physics Since 2000 Immigrant Nobel Winners Since 2000 33 of 85 American winners have been immigrants Percentage of Immigrant Winners Since 2000 39% Source: Royal Swedish Academy of Sciences, National Foundation for American Policy, George Mason University Institute for Immigration Research. -
Detection of Cosmic Rays at the LHC Detection of Cosmic Rays at the LHC
Particle and Astroparticle Physics at the Large Hadron Collider --Hadronic Interactions-- Albert De Roeck CERN, Geneva, Switzerland Antwerp University Belgium UC-Davis California USA NTU, Singapore November 15th 2019 Outline • Introduction on the LHC and LHC physics program • LHC results for Astroparticle physics • Measurements of event characteristics at 13 TeV • Forward measurements • Cosmic ray measurements • LHC and light ions? • Summary The LHC Machine and Experiments MoEDAL LHCf FASER totem CM energy → Run-1: (2010-2012) 7/8 TeV Run-2: (2015-2018) 13 TeV -> Now 8 experiments Run-2 starts proton-proton Run-2 finished 24/10/18 6:00am 2018 2010-2012: Run-1 at 7/8 TeV CM energy Collected ~ 27 fb-1 2015-2018: Run-2 at 13 TeV CM Energy Collected ~ 140 fb-1 2021-2023/24 : Run-3 Expect ⇨ 14 TeV CM Energy and ~ 200/300 fb-1 The LHC is also a Heavy Ion Collider ALICE Data taking during the HI run • All experiments take AA or pA data (except TOTEM) Expected for Run-3: in addition short pO and OO runs ⇨ pO certainly of interest for Cosmic Ray Physics Community! 4 10 years of LHC Operation • LHC: 7 TeV in March 2010 ->The highest energy in the lab! • LHC @ 13 TeV from 2015 onwards March 30 2010 …waiting.. • Most important highlight so far: …since 4:00 am The discovery of a Higgs boson • Many results on Standard Model process measurements, QCD and particle production, top-physics, b-physics, heavy ion physics, searches, Higgs physics • Waiting for the next discovery… -> Searches beyond the Standard Model 12:58 7 TeV collisions!!! New Physics Hunters -
The Large Hadron Collider Lyndon Evans CERN – European Organization for Nuclear Research, Geneva, Switzerland
34th SLAC Summer Institute On Particle Physics (SSI 2006), July 17-28, 2006 The Large Hadron Collider Lyndon Evans CERN – European Organization for Nuclear Research, Geneva, Switzerland 1. INTRODUCTION The Large Hadron Collider (LHC) at CERN is now in its final installation and commissioning phase. It is a two-ring superconducting proton-proton collider housed in the 27 km tunnel previously constructed for the Large Electron Positron collider (LEP). It is designed to provide proton-proton collisions with unprecedented luminosity (1034cm-2.s-1) and a centre-of-mass energy of 14 TeV for the study of rare events such as the production of the Higgs particle if it exists. In order to reach the required energy in the existing tunnel, the dipoles must operate at 1.9 K in superfluid helium. In addition to p-p operation, the LHC will be able to collide heavy nuclei (Pb-Pb) with a centre-of-mass energy of 1150 TeV (2.76 TeV/u and 7 TeV per charge). By modifying the existing obsolete antiproton ring (LEAR) into an ion accumulator (LEIR) in which electron cooling is applied, the luminosity can reach 1027cm-2.s-1. The LHC presents many innovative features and a number of challenges which push the art of safely manipulating intense proton beams to extreme limits. The beams are injected into the LHC from the existing Super Proton Synchrotron (SPS) at an energy of 450 GeV. After the two rings are filled, the machine is ramped to its nominal energy of 7 TeV over about 28 minutes. In order to reach this energy, the dipole field must reach the unprecedented level for accelerator magnets of 8.3 T. -
Department of High Energy Physics: Overview
DEPARTMENT OF HIGH ENERGY PHYSICS 93 6 DEPARTMENT OF HIGH ENERGY PHYSICS PLO401707 Head of Department: Assoc. Professor Helena Balkowska phone: (22) 621-28-04 e-mail: Lena.Bialkowskafuw.edu.pl Overview The activities of the Department f Hgh Energy Physics are centered around experiments performed at accelerators in the following laboratories: • At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: DELPHI* at LEP ee- stora(Te rina - the tests of the Standard Model, b-quark physics, gamina-gami-na interactions and search for Higgs boson and supersymmetric particles - NA48 - the CP-violation and are K decays - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) - studies the gluon polarization in the nucleon - NA49* and WA98 - heavy ion physics, looking for possible effects of the phase transition to te quark- - gluon plasma state • At CELSIUS Storage Ring in Uppsala, Sweden: - WASA - a precise study of near threshold resonance poduction. • At RHIC - study of pp elastic scatterin.g. • At DESY in Hamburg, Germany: - ZEUS - deep inelastic scattering f elections and protons, proton structure functions, dffractive poton- proton interactions. • Super-Karniokande and K2K - a study of neutrino oscillations. The Groups fi-om our Department participated in the construction phase of te experiments, both in hardware and in development of the software used in data analysis. Presently they take part in te data collection, detector performance supervision and data analysis. The Department is also involved -
Furukawa's Technology Contributed to the Discovery of the Higgs Boson
Furukawa Here and There Special About the Furukawa’s technology Higgs boson contributed to the discovery It is an elementary particle, which is the smallest unit in nature. Modern of the Higgs boson physics considers that all phenomena n July 4, the discovery of the Higgs boson in the natural world can be explained called “God particle” received extensive in 17 elementary particles. Discovery of O century? coverage in the press. The European Council Sixteen of the 17 particles, including for Nuclear Research (Conseil Européen pour la What’s so great those that constitute substances about it? Recherche Nucléaire: CERN), headquartered in and those that transmit forces, had Geneva, Switzerland, announced the discovery of a already been discovered. Only the new particle that it deemed to be the Higgs boson, Higgs boson, which functions to which for many years has been the target of a search provide mass (weight) to substances, by physicists around the world. Furukawa Electric had remained unidentified. contributed significantly to what some are calling the discovery of the century. The Higgs boson is referred to as the “God particle” because it has a significant role in the formation of the universe and substances. This made it easier for The birth of the universe elementary particles with Speed mass to gather. Some of Elementary particle Elementary particle of I feel these particles stuck to one light! Higgs boson something another to form the origin of heavy atoms. This is how the Earth, all substances in the universe I see. and humankind are believed to have originated. It is said that if it were no Higgs boson, the human body would be torn apart in one billionth of a second. -
Physicists at Work Interactions
A Inter ctions across physics and education September/October 2007 Focal Point Physicists at Work Inside: Career Paths, Profiled Physics Majors, Uncovered Writing About Science and introducing “Homer Dodge's Notebook” Interactions Inter ctions MAGAZINE across physics and education Issue Editor: John S. Rigden Managing Editor: Daryl Malloy Production Editor: Lissa Reynolds About INTERACTIONS Assistant Editor: Steve Davolt Interactions is a general-interest magazine about physics education. Our mission is to inform and stimulate diverse conversations on teaching and Design: Matthew Payne learning by publishing thought-provoking news, analysis, and commentary Contributing Design: Ayah Oweis on the people, programs, and policies that interact to influence scientific practices and knowledge—and, ultimately, human destiny. Contributing Editors Jane Chambers, Rachel Ivie, Rachel Safier, Reader Comments Pamela Brown, Patrick Mulvey, Martha Heil The editors welcome your response. Send comments, questions or suggestions Publisher: Toufic M. Hakim to [email protected] or mail letters to Interactions Forum, One Physics Communications Director: Robert Headrick Ellipse, 5th Floor, College Park, MD 20740. Please include your full name, mailing address, and daytime contact information. Space is limited and all Editorial Advisory Panel Juan Burciaga published comments are subject to editing. Whitman College, WA Christopher Chiaverina Contributor Guidelines New Trier High School, IL Although most of the articles are commissioned by the editors, we encourage Warren Hein writer queries and story ideas. Email your query, and attach any writing samples, American Association of Physics Teachers, MD to [email protected]. Or mail the letter along with samples to Interactions Robert Hilborn Editor, One Physics Ellipse, College Park, MD 20740. -
Event Recorded by ATLAS When the LHC's Beam 2 Reached Closed
A ‘beam splash’ event recorded by ATLAS when the LHC’s beam 2 reached closed collimators near the detector on 20 November. 12 | CERN “The imminent start-up of the LHC is an event that excites everyone who has an interest in the fundamental physics of the Universe.” Kaname Ikeda, ITER Director-General, CERN Bulletin, 19 October 2009. Physics and Experiments The moment that particle physicists around the world had been The EMCal is an upgrade for ALICE, having received full waiting for finally arrived on 20 November 2009 when protons approval and construction funds only in early 2008. It will detect circulated again round the LHC. Over the following days, the high-energy photons and neutral pions, as well as the neutral machine passed a number of milestones, from the first collisions component of ‘jets’ of particles as they emerge from quark� at 450 GeV per beam to collisions at a total energy of 2.36 TeV gluon plasma formed in collisions between heavy ions; most — a world record. At the same time, the LHC experiments importantly, it will provide the means to select these events on began to collect data, allowing the collaborations to calibrate line. The EMCal is basically a matrix of scintillator and lead, detectors and assess their performance prior to the real attack which is contained in ‘supermodules’ that weigh about eight tonnes. It will consist of ten full supermodules and two partial on high-energy physics in 2010. supermodules. The repairs to the LHC and subsequent consolidation work For the ATLAS Collaboration, crucial repair work included following the incident in September 2008 took approximately modifications to the cooling system for the inner detector.