https://doi.org/10.1140/epjc/s10052-014-3077-y
Regular Article - Experimental Physics
Event-by-event mean pT fluctuations in pp and Pb–Pb collisions at the LHC
1
A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation, Yerevan, Armenia
2
Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
3
Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine
4
Department of Physics and Centre for Astroparticle Physics and Space Science (CAPSS), Bose Institute, Kolkata, India
5
Budker Institute for Nuclear Physics, Novosibirsk, Russia
6
California Polytechnic State University, San Luis Obispo, CA, USA
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Central China Normal University, Wuhan, China
8
Centre de Calcul de l’IN2P3, Villeurbanne, France
9
Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Havana, Cuba
10
Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
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Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City and Mérida, Mexico
12
Centro Fermi-Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Rome, Italy
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Chicago State University, Chicago, USA
14
Commissariat à l’Energie Atomique, IRFU, Saclay, France
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COMSATS Institute of Information Technology (CIIT), Islamabad, Pakistan
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Departamento de Física de Partículas and IGFAE, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
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Department of Physics and Technology, University of Bergen, Bergen, Norway
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Department of Physics, Aligarh Muslim University, Aligarh, India
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Department of Physics, Ohio State University, Columbus, OH, USA
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Department of Physics, Sejong University, Seoul, South Korea
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Department of Physics, University of Oslo, Oslo, Norway
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Dipartimento di Fisica dell’Università ‘La Sapienza’ and Sezione INFN, Rome, Italy
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Dipartimento di Fisica dell’Università and Sezione INFN, Cagliari, Italy
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Dipartimento di Fisica dell’Università and Sezione INFN, Trieste, Italy
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Dipartimento di Fisica dell’Università and Sezione INFN, Turin, Italy
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Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Bologna, Italy
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Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Catania, Italy
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Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Padua, Italy
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Dipartimento di Fisica ‘E.R. Caianiello’ dell’Università and Gruppo Collegato INFN, Salerno, Italy
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Dipartimento di Scienze e Innovazione Tecnologica dell’Università del Piemonte Orientale and Gruppo Collegato INFN, Alessandria, Italy
31
Dipartimento Interateneo di Fisica ‘M. Merlin’ and Sezione INFN, Bari, Italy
32
Division of Experimental High Energy Physics, University of Lund, Lund, Sweden
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Eberhard Karls Universität Tübingen, Tübingen, Germany
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European Organization for Nuclear Research (CERN), Geneva, Switzerland
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Faculty of Engineering, Bergen University College, Bergen, Norway
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Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
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Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic
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Faculty of Science, P.J. Šafárik University, Kosice, Slovakia
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Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
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Gangneung-Wonju National University, Gangneung, South Korea
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Department of Physics, Gauhati University, Guwahati, India
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Helsinki Institute of Physics (HIP), Helsinki, Finland
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Hiroshima University, Hiroshima, Japan
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Indian Institute of Technology Bombay (IIT), Mumbai, India
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Indian Institute of Technology Indore (IITI), Indore, India
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Inha University, Inchon, South Korea
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Institut de Physique Nucléaire d’Orsay (IPNO), Université Paris-Sud, CNRS-IN2P3, Orsay, France
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Institut für Informatik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
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Institut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
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Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany
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Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, CNRS-IN2P3, Strasbourg, France
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Institute for Nuclear Research, Academy of Sciences, Moscow, Russia
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Institute for Subatomic Physics of Utrecht University, Utrecht, The Netherlands
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Institute for Theoretical and Experimental Physics, Moscow, Russia
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Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia
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Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Institute of Physics, Bhubaneswar, India
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Institute of Space Science (ISS), Bucharest, Romania
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Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Instituto de Física, Universidad Nacional Autónoma de México, Mexico City, Mexico
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iThemba LABS, National Research Foundation, Somerset West, South Africa
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Joint Institute for Nuclear Research (JINR), Dubna, Russia
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Konkuk University, Seoul, South Korea
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Korea Institute of Science and Technology Information, Taejeon, South Korea
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KTO Karatay University, Konya, Turkey
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Laboratoire de Physique Corpusculaire (LPC), Clermont Université, Université Blaise Pascal, CNRS-IN2P3, Clermont-Ferrand, France
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Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS-IN2P3, Grenoble, France
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Laboratori Nazionali di Frascati, INFN, Frascati, Italy
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Laboratori Nazionali di Legnaro, INFN, Legnaro, Italy
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Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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Lawrence Livermore National Laboratory, Livermore, CA, USA
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Moscow Engineering Physics Institute, Moscow, Russia
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National Centre for Nuclear Studies, Warsaw, Poland
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National Institute for Physics and Nuclear Engineering, Bucharest, Romania
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National Institute of Science Education and Research, Bhubaneswar, India
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Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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Nikhef, National Institute for Subatomic Physics, Amsterdam, The Netherlands
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Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, UK
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Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež u Prahy, Czech Republic
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Oak Ridge National Laboratory, Oak Ridge, TN, USA
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Petersburg Nuclear Physics Institute, Gatchina, Russia
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Physics Department, Creighton University, Omaha, NE, USA
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Physics Department, Panjab University, Chandigarh, India
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Physics Department, University of Athens, Athens, Greece
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Physics Department, University of Cape Town, Cape Town, South Africa
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Physics Department, University of Jammu, Jammu, India
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Physics Department, University of Rajasthan, Jaipur, India
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Physik Department, Technische Universität München, Munich, Germany
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Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
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Politecnico di Torino, Turin, Italy
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Purdue University, West Lafayette, IN, USA
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Pusan National University, Pusan, South Korea
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Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
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Rudjer Bošković Institute, Zagreb, Croatia
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Russian Federal Nuclear Center (VNIIEF), Sarov, Russia
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Russian Research Centre Kurchatov Institute, Moscow, Russia
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Saha Institute of Nuclear Physics, Kolkata, India
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School of Physics and Astronomy, University of Birmingham, Birmingham, UK
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Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Lima, Peru
100
Sezione INFN, Bari, Italy
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Sezione INFN, Bologna, Italy
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Sezione INFN, Cagliari, Italy
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Sezione INFN, Catania, Italy
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Sezione INFN, Padua, Italy
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Sezione INFN, Rome, Italy
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Sezione INFN, Trieste, Italy
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Sezione INFN, Turin, Italy
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SSC IHEP of NRC Kurchatov institute, Protvino, Russia
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SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS-IN2P3, Nantes, France
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Suranaree University of Technology, Nakhon Ratchasima, Thailand
111
Technical University of Split FESB, Split, Croatia
112
The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Kracòw, Poland
113
Physics Department, The University of Texas at Austin, Austin, TX, USA
114
Universidad Autónoma de Sinaloa, Culiacán, Mexico
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Universidade de São Paulo (USP), São Paulo, Brazil
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Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
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University of Houston, Houston, TX, USA
118
University of Jyväskylä, Jyväskylä, Finland
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University of Liverpool, Liverpool, UK
120
University of Tennessee, Knoxville, TN, USA
121
University of Tokyo, Tokyo, Japan
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University of Tsukuba, Tsukuba, Japan
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University of Zagreb, Zagreb, Croatia
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Université de Lyon, Université Lyon 1, CNRS/IN2P3, IPN-Lyon, Villeurbanne, France
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V. Fock Institute for Physics, St. Petersburg State University, St. Petersburg, Russia
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Variable Energy Cyclotron Centre, Kolkata, India
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Vestfold University College, Tonsberg, Norway
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Warsaw University of Technology, Warsaw, Poland
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Wayne State University, Detroit, MI, USA
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Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary
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Yale University, New Haven, CT, USA
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Yonsei University, Seoul, South Korea
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Zentrum für Technologietransfer und Telekommunikation (ZTT), Fachhochschule Worms, Worms, Germany
134
CERN, 1211, Geneva 23, Switzerland
* e-mail: alice-publications@cern.ch
Received:
22
July
2014
Accepted:
12
September
2014
Published online:
15
October
2014
Event-by-event fluctuations of the mean transverse momentum of charged particles produced in pp collisions at √s = 0.9, 2.76 and 7 TeV, and Pb–Pb collisions at √sNN = 2.76 TeV are studied as a function of the charged-particle multiplicity using the ALICE detector at the LHC. Dynamical fluctuations indicative of correlated particle emission are observed in all systems. The results in pp collisions show little dependence on collision energy. The Monte Carlo event generators PYTHIA and PHOJET are in qualitative agreement with the data. Peripheral Pb–Pb data exhibit a similar multiplicity dependence as that observed in pp. In central Pb–Pb, the results deviate from this trend, featuring a significant reduction of the fluctuation strength. The results in Pb–Pb are in qualitative agreement with previous measurements in Au–Au at lower collision energies and with expectations from models that incorporate collective phenomena.
© SIF and Springer-Verlag Berlin Heidelberg, 2014