Multiplicity dependence of light-flavor hadron production in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi><mml:mi>p</mml:mi></mml:mrow></mml:math> collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>7</mml:mn><mml:mspace width="0.16em"/><mml:mi>TeV</mml:mi></mml:mrow></mml:math>
S. AcharyaVariable Energy Cyclotron Centre, Homi Bhabha National Institute, Kolkata, IndiaFernando Torales AcostaDepartment of Physics, University of California, Berkeley, California, USAD. AdamováNuclear Physics Institute of the Czech Academy of Sciences, Řež u Prahy, Czech RepublicA. AdlerJohann-Wolfgang-Goethe Universität Frankfurt Institut für Informatik, Fachbereich Informatik und Mathematik, Frankfurt, GermanyJonatan AdolfssonLund University Department of Physics, Division of Particle Physics, Lund, SwedenM. M. AggarwalPhysics Department, Panjab University, Chandigarh, IndiaG. Aglieri RinellaEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandM. AgnelloDipartimento DISAT del Politecnico and Sezione INFN, Turin, ItalyN. AgrawalIndian Institute of Technology Bombay (IIT), Mumbai, IndiaZ. AhammedVariable Energy Cyclotron Centre, Homi Bhabha National Institute, Kolkata, IndiaS. U. AhnKorea Institute of Science and Technology Information, Daejeon, Republic of KoreaS. AiolaYale University, New Haven, Connecticut, USAA. AkindinovInstitute for Theoretical and Experimental Physics, Moscow, RussiaM. Al-TuranyResearch Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, GermanyS. N. AlamVariable Energy Cyclotron Centre, Homi Bhabha National Institute, Kolkata, IndiaD. S. D. AlbuquerqueUniversidade Estadual de Campinas (UNICAMP), Campinas, BrazilD. AleksandrovNational Research Centre Kurchatov Institute, Moscow, RussiaB. AlessandroINFN, Sezione di Torino, Turin, ItalyH. M. AlfandaCentral China Normal University, Wuhan, ChinaR. Alfaro MolinaInstituto de Física, Universidad Nacional Autónoma de México, Mexico City, MexicoY. AliCOMSATS Institute of Information Technology (CIIT), Islamabad, PakistanA. AliciCentro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Rome, ItalyA. AlkinBogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, Kiev, UkraineJ. AlmeDepartment of Physics and Technology, University of Bergen, Bergen, NorwayT. AltInstitut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, GermanyL. AltenkamperDepartment of Physics and Technology, University of Bergen, Bergen, NorwayI. AltsybeevSt. Petersburg State University, St. Petersburg, RussiaM. N. AnaamCentral China Normal University, Wuhan, ChinaC. AndreiHoria Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, RomaniaD. AndreouEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandH. A. AndrewsSchool of Physics and Astronomy, University of Birmingham, Birmingham, United KingdomA. AndronicResearch Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, GermanyM. AngelettiEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandV. AnguelovPhysikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, GermanyC. AnsonCreighton University, Omaha, Nebraska, USAT. AntičićRudjer Bošković Institute, Zagreb, CroatiaF. AntinoriINFN, Sezione di Padova, Padova, ItalyP. AntonioliINFN, Sezione di Bologna, Bologna, ItalyR. AnwarUniversity of Houston, Houston, Texas, USAN. ApadulaLawrence Berkeley National Laboratory, Berkeley, California, USAL. AphecetcheSUBATECH, IMT Atlantique, Université de Nantes, CNRS-IN2P3, Nantes, FranceH. AppelshäuserInstitut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, GermanyS. ArcelliDipartimento di Fisica e Astronomia dell'Università and Sezione INFN, Bologna, ItalyR. ArnaldiINFN, Sezione di Torino, Turin, ItalyI. C. ArseneDepartment of Physics, University of Oslo, Oslo, NorwayM. ArslandokPhysikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, GermanyA. AugustinusEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandR. AverbeckResearch Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, GermanyM. D. AzmiDepartment of Physics, Aligarh Muslim University, Aligarh, IndiaA. BadaláINFN, Sezione di Catania, Catania, ItalyY. W. BaekGangneung-Wonju National University, Gangneung, Republic of KoreaS. BagnascoINFN, Sezione di Torino, Turin, ItalyR. BailhacheInstitut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, GermanyR. BalaPhysics Department, University of Jammu, Jammu, IndiaA. BaldisseriUniversité Paris-Saclay Centre dÉtudes de Saclay (CEA), IRFU, Department de Physique Nucléaire (DPhN), Saclay, FranceM. BallHelmholtz-Institut für Strahlen- und Kernphysik, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, GermanyR. C. BaralNational Institute of Science Education and Research, Homi Bhabha National Institute, Jatni, IndiaA. M. BarbanoDipartimento di Fisica dell'Università and Sezione INFN, Turin, ItalyR. BarberaDipartimento di Fisica e Astronomia dell'Università and Sezione INFN, Catania, ItalyF. BarileINFN, Sezione di Bari, Bari, ItalyL. BarioglioDipartimento di Fisica dell'Università and Sezione INFN, Turin, ItalyG. G. BarnaföldiWigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, HungaryL. S. BarnbyNuclear Physics Group, STFC Daresbury Laboratory, Daresbury, United KingdomV. BarretUniversité Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, FranceP. BartaliniCentral China Normal University, Wuhan, ChinaK. BarthEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandE. BartschInstitut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, GermanyN. BastidUniversité Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, FranceS. BasuWayne State University, Detroit, Michigan, USAG. BatigneSUBATECH, IMT Atlantique, Université de Nantes, CNRS-IN2P3, Nantes, FranceB. BatyunyaJoint Institute for Nuclear Research (JINR), Dubna, RussiaP. C. BatzingDepartment of Physics, University of Oslo, Oslo, NorwayJ. L. Bazo AlbaSección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Lima, PeruI. G. BeardenNiels Bohr Institute, University of Copenhagen, Copenhagen, DenmarkH. P. BeckPhysikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, GermanyC. BeddaInstitute for Subatomic Physics, Utrecht University/Nikhef, Utrecht, NetherlandsN. K. BeheraInha University, Incheon, Republic of KoreaI. BelikovUniversité de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France, Strasbourg, FranceF. BelliniEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandH. Martı́nezHigh Energy Physics Group, Universidad Autónoma de Puebla, Puebla, MexicoR. BellwiedUniversity of Houston, Houston, Texas, USAL. G. E. BeltranUniversidad Autónoma de Sinaloa, Culiacán, MexicoV. BelyaevNRNU Moscow Engineering Physics Institute, Moscow, RussiaG. BencediWigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, HungaryS. BeolèDipartimento di Fisica dell'Università and Sezione INFN, Turin, ItalyA. BercuciHoria Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, RomaniaY. BerdnikovPetersburg Nuclear Physics Institute, Gatchina, RussiaD. BerényiWigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, HungaryR. A. BertensUniversity of Tennessee, Knoxville, Tennessee, USAD. BerzanoEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandL. BetevEuropean Organization for Nuclear Research (CERN), Geneva, SwitzerlandP. P. BhaduriVariable Energy Cyclotron Centre, Homi Bhabha National Institute, Kolkata, IndiaA. BhasinPhysics Department, University of Jammu, Jammu, IndiaI. R. BhatPhysics Department, University of Jammu, Jammu, IndiaH. BhattIndian Institute of Technology Bombay (IIT), Mumbai, IndiaB. BhattacharjeeGauhati University, Department of Physics, Guwahati, IndiaJ. BhomThe Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, PolandA. BianchiDipartimento di Fisica dell'Università and Sezione INFN, Turin, ItalyL. BianchiUniversity of Houston, Houston, Texas, USAN. BianchiINFN, Laboratori Nazionali di Frascati, Frascati, Italy
2019lv
ABI
Abstract
Comprehensive results on the production of unidentified charged particles, ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}, {\mathrm{K}}^{\ifmmode\pm\else\textpm\fi{}}, {\mathrm{K}}_{\mathrm{S}}^{0}, {\mathrm{K}}^{*}{(892)}^{0}, p, \overline{p}, \ensuremath{\phi}$(1020), $\mathrm{\ensuremath{\Lambda}}, \overline{\mathrm{\ensuremath{\Lambda}}}, {\mathrm{\ensuremath{\Xi}}}^{\ensuremath{-}}, {\overline{\mathrm{\ensuremath{\Xi}}}}^{+}, {\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}}$, and ${\overline{\mathrm{\ensuremath{\Omega}}}}^{+}$ hadrons in proton-proton ($pp$) collisions at $\sqrt{s}=7$ TeV at midrapidity ($|y|<0.5$) as a function of charged-particle multiplicity density are presented. In order to avoid autocorrelation biases, the actual transverse momentum (${p}_{\mathrm{T}}$) spectra of the particles under study and the event activity are measured in different rapidity windows. In the highest multiplicity class, the charged-particle density reaches about 3.5 times the value measured in inelastic collisions. While the yield of protons normalized to pions remains approximately constant as a function of multiplicity, the corresponding ratios of strange hadrons to pions show a significant enhancement that increases with increasing strangeness content. Furthermore, all identified particle-to-pion ratios are shown to depend solely on charged-particle multiplicity density, regardless of system type and collision energy. The evolution of the spectral shapes with multiplicity and hadron mass shows patterns that are similar to those observed in $p$-Pb and Pb-Pb collisions at Large Hadron Collider energies. The obtained ${p}_{\mathrm{T}}$ distributions and yields are compared to expectations from QCD-based $pp$ event generators as well as to predictions from thermal and hydrodynamic models. These comparisons indicate that traces of a collective, equilibrated system are already present in high-multiplicity $pp$ collisions.
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Cited by 40 references