DOCSLIB.ORG

Femtoscopy of Proton-Proton Collisions in the ALICE Experiment

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Femtoscopy of proton-proton collisions in the ALICE experiment DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Nicolas Bock, B.Sc. B.Eng., M.Sc. Graduate Program in Physics The Ohio State University 2011 Dissertation Committee: Professor Thomas J. Humanic, Advisor Professor Michael Lisa #1 Professor Klaus Honscheid #2 Professor Richard Furnstahl #3 c Copyright by Nicolas Bock 2011 Abstract The Large Ion Collider Experiment (ALICE) at CERN has been designed to study matter at extreme conditions of temperature and pressure, with the long term goal of observing deconfined matter (free quarks and gluons), study its properties and learn more details about the phase diagram of nuclear matter. The ALICE experiment provides excellent particle tracking capabilities in high multiplicity proton-proton and heavy ion collisions, allowing to carry out detailed research of nuclear matter. This dissertation presents the study of the space time structure of the particle emission region, also known as femtoscopy, in proton- proton collisions at 0.9, 2.76 and 7.0 TeV. The emission region can be characterized by taking advantage of the Bose-Einstein effect for identical particles, which causes an enhancement of produced identical pairs at low relative momentum. The geometry of the emission region is related to the relative momentum distribution of all pairs by the Fourier transform of the source function, therefore the measurement of the final relative momentum distribution allows to extract the initial space-time characteristics. Results show that there is a clear dependence of the femtoscopic radii on event multiplicity as well as transverse momentum, a signature of the transition of nuclear matter into its fundamental components and also of strong interaction among these. The present work also considers a physics motivated parametrization of non-femtoscopic correlations to characterize the background signal. It is shown that at these high energies and multiplicities this parametrization does not work as it does for lower energies. A special chapter containing the detailed study of possible signatures of black hole formation is also presented. ii Acknowledgments I would like to thank my advisor Dr. Tom Humanic for all your support and guidance during these Ph.D. years, it has been a great pleasure to learn from you and work with you in such a great project as is the ALICE experiment at CERN. Too bad we did not detect any black holes, but maybe at 14 TeV. Thank you also for all your encouragement to advance my career at conferences and workshops. My co-advisor Dr. Mike Lisa: It was always very enlightening to go to your office and show you results or even code as you always had an answer to my questions. The Experimental Heavy Ion Group at Ohio State: Chris Anson, Zibi Chajecki, Dave Truesdale, Matt Steinpreis. The Femtoscopy Group at CERN: Adam Kisiel, Dariusz Miskowiec, Sebastian Huber, Jorge Mercado, Johanna Gramling, and Mads Stormo Nielsen. My Collaborators and friends at ALICE and CERN: Mario Sitta, Francesco Prino, Dhe- van Ghandagaran, Lucy Renshall, Carnita Hervet, Ulla Tihinen, Bjorn Nielsen, Emmanuelle Biolcati and Stephania Beole. I would also like to thank all the professors at OSU that contributed in one way or another to my formation as a physicist: (in no particular order): Dr. David Stroud, Dr. Eric Braaten, Dr. John Beacom, Dr. Junko Shigemitsu, Dr. Dick Furnstahl, Dr. Ulrich Heinz, Dr. Klaus Honscheid, Dr. Yuri Kovchegov, Dr. Julia Meyer, Dr. Samir Matur. Many thanks to the OSU Physics Department staff with whom I interacted on many occasions: Mary Kay Jackson, Arnay Tate, Beth Deinlein, Brenda Mellet, Karen Kitts, Yavonne McGarry. I wish acknowledge the support of the U.S. National Science Foundation under grant PHY-0970048, and to acknowledge computing support from the Ohio Supercomputing Cen- ter. I would like to thank the Physics Department at OSU for the continued support and the great opportunity of becoming a PhD here. I enjoyed and learned a lot from all the classes I took, and the experience as a Teaching Associate was also very rewarding. Finally I wish to thank my family for their constant support. iii Vita April 10, 1979 . Born| Bogot´a,Colombia January 2002 - September 2004 . Undergraduate Teaching Associate, Uni- versidad de los Andes, Bogot´aColombia September 18, 2004 . B.S. Physics, Universidad de los Andes, Bogot´aColombia September 18, 2004 . B.S. Mechanical Engineering, Universidad de los Andes, Bogot´aColombia January 2005 - July 2006 . Adjunct Faculty Professor, Universidad Javeriana, Bogot´aColombia January 2006 - July 2006 . Adjunct Faculty Professor, Universidad del Bosque, Bogot´aColombia September 2006 - August 2009 . Graduate Teaching Associate, The Ohio State University, Columbus Ohio August 31, 2009 . M.S. Physics, The Ohio State University, Columbus, Ohio September 2009 - August 2011 . Graduate Research Associate, The Ohio State University, Columbus Ohio Publications in refereed journals 1. Nicolas Bock for the ALICE Collaboration, Femtoscopy and energy-momentum con- servation effects in proton-proton collisions at 900 GeV in ALICE. Workshop for young scientists on the physics of ultra-relativistic heavy ion collisions, June 21 -26, La Londe Les Maures, France. 2011 J. Phys.: Conf. Ser. 270 012022, arXiv:1009.3157v1 [hep-ex]. 2. Nicolas Bock, Thomas J. Humanic, Quantitative Calculations for Black Hole Pro- duction at the Large Hadron Collider, Int.J.Mod.Phys.A24:1105-1118,2009. iv 3. B Alessandro et al, Operation and calibration of the Silicon Drift Detectors of the ALICE experiment during the 2008 cosmic ray data taking period, 2010 JINST 5 P04004 Conference Proceedings 1. Nicolas Bock, Energy momentum conservation effects on two-particle correlation func- tions. VI Workshop on Particle Correlations and Femtoscopy, September 14-17, 2010, Kiev, Ukraine. arXiv:1101.5241v1 [hep-ex] (2010). Submitted to Physics of Elementary Particles and Atomic Nuclei, Letters. Publications with the ALICE Collaboration 1. The ALICE Collaboration, Two-pion Bose-Einstein correlations in pp collisions at p s 900 GeV at the LHC, Phys. Rev. D 82, 052001 (2010) p 2. The ALICE Collaboration, Femtoscopy of pp collisions at s=0.9 and 7 TeV at the LHC with two-pion Bose-Einstein correlations, arXiv:1101.3665v1 [hep-ex], To be published in Physical Review C. 3. The ALICE Collaboration, Two-pion Bose-Einstein correlations in central PbPb col- p lisions at (sNN ) = 2.76 TeV ALICE Collaboration, Phys.Lett.B 696:328-337 2011, arXiv:1012.4035v2 [nucl-ex]. Invited Presentations 1. HBT Interferometry with the ALICE experiment 26th Lake Louise Winter Institute, Lake Louise, Canada. Feb 20-26, 2011 2. Energy-momentum conservation effects on the two-particle correlation function VI. Workshop on Particle Correlations and Femtoscopy, Bogolyubov institute for the- oretical physics Kiev, Ukraine. Sep 14 -18, 2010 v 3. Femtoscopy and energy-momentum conservation effects in ALICE Hot Quarks: Physics of ultra relativistic nucleus-nucleus collisions, La Londe Les Maures, France. June 21 - 27 2010 4. Improving femtoscopy by characterizing energy-momentum conservation effects Hayes Graduate Research Forum, The Ohio State University, Columbus Ohio. May 1 2010 5. Two pion femtosopy at 7 and 14 TeV pp collisions V. Workshop on Particle Correlations and Femtoscopy, CERN, Geneva, Switzerland. October 14 -17 2009. Full List of Publications with the ALICE Collaboration 1. The ALICE Collaboration, Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at 2.76 TeV, arXiv:1105.3865v1 [nucl-ex], To be pub- lished in Physical Review Letters 2. The ALICE Collaboration, Production of pions, kaons and protons in pp collisions at p s= 900 GeV with ALICE at the LHC, Eur.Phys.J.C 71(6): 1655, 2011 3. The ALICE Collaboration, Rapidity and transverse momentum dependence of inclu- p sive J/psi production in pp collisions at s=7 TeV, arXiv:1105.0380v1 [hep-ex], To be published in Phys. Lett. B 4. The ALICE Collaboration, Strange particle production in proton-proton collisions at p s = 0.9 TeV with ALICE at the LHC, Eur. Phys. J. C 71 (3), 1594 (2011) 5. The ALICE Collaboration, Centrality dependence of the charged-particle multiplicity p density at mid-rapidity in Pb-Pb collisions at sNN = 2.76 TeV, Phys. Rev. Lett. 106, 032301 (2011) 6. The ALICE Collaboration, Suppression of Charged Particle Production at Large p Transverse Momentum in Central Pb-Pb Collisions at sNN = 2.76 TeV, Phys. Lett. B 696 (2011) 30-39 vi 7. The ALICE Collaboration, Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV, Phys. Rev. Lett. 105, 252302 (2010) 8. The ALICE Collaboration, Charged-particle multiplicity density at mid-rapidity in p central Pb-Pb collisions at sNN = 2.76 TeV, Phys. Rev. Lett. 105, 252301 (2010) 9. The ALICE Collaboration, Transverse momentum spectra of charged particles in pro- p tonproton collisions at s=900 GeV with ALICE at the LHC, Physics Letters B 693 (2010) 5368 10. The ALICE Collaboration, Midrapidity Antiproton-to-Proton Ratio in pp Collisons p at s=0.9 and 7 TeV Measured by the ALICE Experiment, Phys Rev Lett Vol.105, No.7, (2010) 11. The ALICE Collaboration, Charged-particle multiplicity measurement in protonproton p collisions at s=7 TeV with ALICE at LHC, Eur. Phys. J. C (2010) 68: 345354 12. The ALICE Collaboration, Charged-particle multiplicity measurement in protonproton p collisions at s=0.9 and 2.36 TeV with ALICE at LHC, Eur. Phys. J. C (2010) 68: 89108 13. The ALICE Collaboration, Alignment of the ALICE Inner Tracking System with cosmic-ray tracks, J. Instrum. 5, P03003 14. The ALICE Collaboration, First protonproton collisions at the LHC as observed with the ALICE detector: measurement of the charged-particle pseudorapidity density at p s=900 GeV, Eur.
Recommended publications
  • CERN Courier–Digital Edition

    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.
  • 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

    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.
  • Proton Driven Plasma Wakefield Acceleration in AWAKE

    Proton Driven Plasma Wakefield Acceleration in AWAKE

    Proton Driven Plasma Article submitted to journal Wakefield Acceleration in Subject Areas: AWAKE Plasma Wakefield Acceleration, 1 1 Proton Driven, Electron Acceleration E. Gschwendtner , M. Turner , **Author List Continues Next Page** Keywords: AWAKE, Plasma Wakefield Acceleration, Seeded Self Modulation In this article, we briefly summarize the experiments Author for correspondence: performed during the first Run of the Advanced Insert corresponding author name Wakefield Experiment, AWAKE, at CERN (European e-mail: [email protected] Organization for Nuclear Research). The final goal of AWAKE Run 1 (2013 - 2018) was to demonstrate that 10-20 MeV electrons can be accelerated to GeV- energies in a plasma wakefield driven by a highly- relativistic self-modulated proton bunch. We describe the experiment, outline the measurement concept and present first results. Last, we outline our plans for the future. 1 Continued Author List 2 E. Adli2,A. Ahuja1,O. Apsimon3;4,R. Apsimon3;4, A.-M. Bachmann1;5;6,F. Batsch1;5;6 C. Bracco1,F. Braunmüller5,S. Burger1,G. Burt7;4, B. Buttenschön8,A. Caldwell5,J. Chappell9, E. Chevallay1,M. Chung10,D. Cooke9,H. Damerau1, L.H. Deubner11,A. Dexter7;4,S. Doebert1, J. Farmer12, V.N. Fedosseev1,R. Fiorito13;4,R.A. Fonseca14,L. Garolfi1,S. Gessner1, B. Goddard1, I. Gorgisyan1,A.A. Gorn15;16,E. Granados1,O. Grulke8;17, A. Hartin9,A. Helm18, J.R. Henderson7;4,M. Hüther5, M. Ibison13;4,S. Jolly9,F. Keeble9,M.D. Kelisani1, S.-Y. Kim10, F. Kraus11,M. Krupa1, T. Lefevre1,Y. Li3;4,S. Liu19,N. Lopes18,K.V. Lotov15;16, M. Martyanov5, S.
  • Slides Lecture 1

    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
  • Arxiv:2001.07837V2 [Hep-Ex] 4 Jul 2020 Scale Funding Will Be Requested at Different Stages Across the Globe

    Arxiv:2001.07837V2 [Hep-Ex] 4 Jul 2020 Scale Funding Will Be Requested at Different Stages Across the Globe

    Brazilian Participation in the Next-Generation Collider Experiments W. L. Aldá Júniora C. A. Bernardesb D. De Jesus Damiãoa M. Donadellic D. E. Martinsd G. Gil da Silveirae;a C. Henself H. Malbouissona A. Massafferrif E. M. da Costaa C. Mora Herreraa I. Nastevad M. Rangeld P. Rebello Telesa T. R. F. P. Tomeib A. Vilela Pereiraa aDepartamento de Física Nuclear e Altas Energias, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, CEP 20550-900, Rio de Janeiro, Brazil bUniversidade Estadual Paulista (Unesp), Núcleo de Computação Científica Rua Dr. Bento Teobaldo Ferraz, 271, 01140-070, Sao Paulo, Brazil cInstituto de Física, Universidade de São Paulo (USP), Rua do Matão, 1371, CEP 05508-090, São Paulo, Brazil dUniversidade Federal do Rio de Janeiro (UFRJ), Instituto de Física, Caixa Postal 68528, 21941-972 Rio de Janeiro, Brazil eInstituto de Física, Universidade Federal do Rio Grande do Sul , Av. Bento Gonçalves, 9550, CEP 91501-970, Caixa Postal 15051, Porto Alegre, Brazil f Centro Brasileiro de Pesquisas Físicas (CBPF), Rua Dr. Xavier Sigaud, 150, CEP 22290-180 Rio de Janeiro, RJ, Brazil E-mail: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected] Abstract: This proposal concerns the participation of the Brazilian High-Energy Physics community in the next-generation collider experiments.
  • Detection of Cosmic Rays at the LHC Detection of Cosmic Rays at the LHC

    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

    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.
  • Prospects of Measuring the Branching Fraction of the Higgs Boson

    Prospects of Measuring the Branching Fraction of the Higgs Boson

    ILD-PHYS-2020-002 09 September 2020 Prospects of measuring the branching fraction of the Higgs boson decaying into muon pairs at the International Linear Collider Shin-ichi Kawada∗, Jenny List∗, Mikael Berggren∗ ∗ DESY, Notkestraße 85, 22607 Hamburg, Germany Abstract The prospects for measuring the branching fraction of H µ+µ at the International → − Linear Collider (ILC) have been evaluated based on a full detector simulation of the Interna- tional Large Detector (ILD) concept, considering centre-of-mass energies (√s) of 250 GeV + + and 500 GeV. For both √s cases, the two final states e e− qqH and e e− ννH 1 → → 1 have been analyzed. For integrated luminosities of 2 ab− at √s = 250 GeV and 4 ab− at √s = 500 GeV, the combined precision on the branching fraction of H µ+µ is estim- → − ated to be 17%. The impact of the transverse momentum resolution for this analysis is also studied∗. arXiv:2009.04340v1 [hep-ex] 9 Sep 2020 ∗This work was carried out in the framework of the ILD concept group 1 Introduction 1 Introduction A Standard Model (SM)-like Higgs boson with mass of 125 GeV has been discovered by the ATLAS ∼ and CMS experiments at the Large Hadron Collider (LHC) [1, 2]. Recently, the decay mode of the Higgs boson to bottom quarks H bb has been observed at the LHC [3, 4], as well as the ttH production → process [5, 6], both being consistent with the SM prediction. However, there are several important questions to which the SM does not offer an answer: it neither explains the hierarchy problem, nor does it address the nature of dark matter, the origin of cosmic inflation, or the baryon-antibaryon asymmetry in the universe.
  • Event Recorded by ATLAS When the LHC's Beam 2 Reached Closed

    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.
  • Tuning the HF Calorimeter Gflash Simulation Using CMS Data Jeff Van Harlingen1 Rahmat Rahmat2 Eduardo Ibarra García Padilla3

    Tuning the HF Calorimeter Gflash Simulation Using CMS Data Jeff Van Harlingen1 Rahmat Rahmat2 Eduardo Ibarra García Padilla3

    Tuning the HF Calorimeter GFlash Simulation Using CMS Data Jeff Van Harlingen1 Rahmat Rahmat2 Eduardo Ibarra García Padilla3 1Madison Junior High School (NCUSD 203) 2Mid-America Christian University 3Universidad Nacional Autónoma de México Outline .LHC and CMS Description .Particle Collisions .The Higgs Boson .HF Calorimeter at CMS .GFlash Speed and Accuracy Tuning .Future Applications Large Hadron Collider (LHC) .Located at CERN in Switzerland .Four major experiments (CMS, ATLAS, ALICE, and LHCb) .The LHC is a 27-km ring lined with superconducting magnets Large Hadron Collider (LHC) .Two particle-beams are accelerated close to the speed of light .Collisions between these high-energy beams, create particles that could tell us about the fundamental building blocks of the universe Compact Muon Solenoid (CMS) .14,000 Ton Detector .One of the largest science collaborations in history: .4,300 physicists, engineers, technicians, etc. .182 Universities and institutions .42 countries represented .21 meters long .15 meters wide .15 meters high Compact Muon Solenoid (CMS) Compact Muon Solenoid (CMS) Compact Muon Solenoid (CMS) Solenoid Creates 4 Tesla magnetic field to bend the path of particles Silicon Tracker Measuring the positions of passing charged particles allows us to reconstruct their tracks. Electromagnetic Calorimeter Measure the energies of electrons and photons Hadronic Calorimeter Measure the energies of hadronic particles (Pions) Muon Chambers Tracks Muon Trajectories Hadronic Forward Calorimeter Measure the energies of hadronic and electromagnetic particles How do we detect particles? “Just as hunters can identify animals from tracks in mud or snow, physicists identify subatomic particles from the traces they leave in detectors” -CERN .Accelerators .Tracking Devices .Calorimeters .Particle ID Detectors Step-by-Step Collision 1.
  • A BOINC-Based Volunteer Computing Infrastructure for Physics Studies At

    A BOINC-Based Volunteer Computing Infrastructure for Physics Studies At

    Open Eng. 2017; 7:379–393 Research article Javier Barranco, Yunhai Cai, David Cameron, Matthew Crouch, Riccardo De Maria, Laurence Field, Massimo Giovannozzi*, Pascal Hermes, Nils Høimyr, Dobrin Kaltchev, Nikos Karastathis, Cinzia Luzzi, Ewen Maclean, Eric McIntosh, Alessio Mereghetti, James Molson, Yuri Nosochkov, Tatiana Pieloni, Ivan D. Reid, Lenny Rivkin, Ben Segal, Kyrre Sjobak, Peter Skands, Claudia Tambasco, Frederik Van der Veken, and Igor Zacharov LHC@Home: a BOINC-based volunteer computing infrastructure for physics studies at CERN https://doi.org/10.1515/eng-2017-0042 Received October 6, 2017; accepted November 28, 2017 1 Introduction Abstract: The LHC@Home BOINC project has provided This paper addresses the use of volunteer computing at computing capacity for numerical simulations to re- CERN, and its integration with Grid infrastructure and ap- searchers at CERN since 2004, and has since 2011 been plications in High Energy Physics (HEP). The motivation expanded with a wider range of applications. The tradi- for bringing LHC computing under the Berkeley Open In- tional CERN accelerator physics simulation code SixTrack frastructure for Network Computing (BOINC) [1] is that enjoys continuing volunteers support, and thanks to vir- available computing resources at CERN and in the HEP tualisation a number of applications from the LHC ex- community are not sucient to cover the needs for nu- periment collaborations and particle theory groups have merical simulation capacity. Today, active BOINC projects joined the consolidated LHC@Home BOINC project. This together harness about 7.5 Petaops of computing power, paper addresses the challenges related to traditional and covering a wide range of physical application, and also virtualized applications in the BOINC environment, and particle physics communities can benet from these re- how volunteer computing has been integrated into the sources of donated simulation capacity.
  • Compact Muon Solenoid Detector (CMS) & the Token Bit Manager

    Compact Muon Solenoid Detector (CMS) & the Token Bit Manager

    Compact Muon Solenoid Detector (CMS) & The Token Bit Manager (TBM) Alex Armstrong & Wyatt Behn Mentor: Dr. Andrew Ivanov Part 1: The TBM and CMS ● Understanding how the LHC and the CMS detector work as a unit ● Learning how the TBM is a vital part of the CMS detector ● Physically handling and testing the TBM chips in the Hi- bay Motivation ● The CMS detector requires upgrades to handle increased beam luminosity ● Minimizing data loss in the innermost regions of the detector will therefore require faster, lighter, more durable, and more functional TBM chips than the current TBM 05a We tested many of the new TBM08b and TBM09 chips to guarantee that they meet certain standards of operation. CERN Conseil Européen pour la Recherche Nucléaire (European Council for Nuclear Research) (1952) Image Credit:: http://home.web.cern.ch/ CERN -> LHC Large Hadron Collider (2008) Two proton beams 1) ATLAS travel in opposite 2) ALICE directions until 3) LHCb collision in detectors 4) CMS Image Credit: hep://home.web.cern.ch/topics/large--‐hadron--‐collider Image Credit: http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/collisions.htm CERN -> LHC -> CMS Compact Muon Solenoid (2008) Image Credit: hep://cms.web.cern.ch/ Image Credit: http://home.web.cern.ch/about/experiments/cms CMS Detector System Image Credit: hep://home.web.cern.ch/about/experiments/cms Inner Silicon Tracker Semiconductor detector technology used to measure and time stamp position of charged particles Inner layers consist of pixels for highest possible resolution Outer layers