https://doi.org/10.1140/epjc/s10052-010-1339-x
Regular Article - Experimental Physics
Charged-particle multiplicity measurement in proton–proton collisions at 
and 2.36 TeV with ALICE at LHC
1
Dipartimento di Scienze e Tecnologie Avanzate dell’Università del Piemonte Orientale and Gruppo Collegato INFN, Alessandria, Italy
2
Department of Physics, Aligarh Muslim University, Aligarh, India
3
National Institute for Nuclear and High Energy Physics (NIKHEF), Amsterdam, Netherlands
4
Physics Department, University of Athens, Athens, Greece
5
Dipartimento Interateneo di Fisica ‘M. Merlin’ and Sezione INFN, Bari, Italy
6
Sezione INFN, Bari, Italy
7
China Institute of Atomic Energy, Beijing, China
8
Department of Physics and Technology, University of Bergen, Bergen, Norway
9
Faculty of Engineering, Bergen University College, Bergen, Norway
10
Lawrence Berkeley National Laboratory, Berkeley, CA, USA
11
Institute of Physics, Bhubaneswar, India
12
School of Physics and Astronomy, University of Birmingham, Birmingham, UK
13
Dipartimento di Fisica dell’Università and Sezione INFN, Bologna, Italy
14
Sezione INFN, Bologna, Italy
15
Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
16
Institute of Space Sciences (ISS), Bucharest, Romania
17
National Institute for Physics and Nuclear Engineering, Bucharest, Romania
18
KFKI Research Institute for Particle and Nuclear Physics, Hungarian Academy of Sciences, Budapest, Hungary
19
Dipartimento di Fisica dell’Università and Sezione INFN, Cagliari, Italy
20
Sezione INFN, Cagliari, Italy
21
Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
22
Physics Department, iThemba Laboratories, University of Cape Town, Cape Town, South Africa
23
Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Catania, Italy
24
Sezione INFN, Catania, Italy
25
Physics Department, Panjab University, Chandigarh, India
26
Laboratoire de Physique Corpusculaire (LPC), Clermont Université, Université Blaise Pascal, CNRS-IN2P3, Clermont-Ferrand, France
27
Department of Physics, Ohio State University, Columbus, OH, USA
28
Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
29
The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
30
Universidad Autónoma de Sinaloa, Culiacán, Mexico
31
Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
32
Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Germany
33
Wayne State University, Detroit, MI, USA
34
Joint Institute for Nuclear Research (JINR), Dubna, Russia
35
Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
36
Institut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
37
Laboratori Nazionali di Frascati, INFN, Frascati, Italy
38
Petersburg Nuclear Physics Institute, Gatchina, Russia
39
European Organization for Nuclear Research (CERN), Geneva, Switzerland
40
Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier, CNRS-IN2P3, Institut Polytechnique de Grenoble, Grenoble, France
41
Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Havana, Cuba
42
Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
43
Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
44
Hiroshima University, Hiroshima, Japan
45
University of Houston, Houston, TX, USA
46
Physics Department, University of Rajasthan, Jaipur, India
47
Physics Department, University of Jammu, Jammu, India
48
Helsinki Institute of Physics (HIP) and University of Jyväskylä, Jyväskylä, Finland
49
Gangneung-Wonju National University, Gangneung, South Korea
50
Scientific Research Technological Institute of Instrument Engineering, Kharkov, Ukraine
51
Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine
52
University of Tennessee, Knoxville, TN, USA
53
Saha Institute of Nuclear Physics, Kolkata, India
54
Variable Energy Cyclotron Centre, Kolkata, India
55
Fachhochschule Köln, Köln, Germany
56
Faculty of Science, P.J. Šafárik University, Košice, Slovakia
57
Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovakia
58
Laboratori Nazionali di Legnaro, INFN, Legnaro, Italy
59
Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Lima, Peru
60
Lawrence Livermore National Laboratory, Livermore, CA, USA
61
Division of Experimental High Energy Physics, University of Lund, Lund, Sweden
62
Université de Lyon 1, CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, Lyon, France
63
Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
64
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
65
Instituto de Física, Universidad Nacional Autónoma de México, Mexico City, Mexico
66
Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City and Mérida, Mexico
67
Institute for Nuclear Research, Academy of Sciences, Moscow, Russia
68
Institute for Theoretical and Experimental Physics, Moscow, Russia
69
Moscow Engineering Physics Institute, Moscow, Russia
70
Russian Research Centre Kurchatov Institute, Moscow, Russia
71
Indian Institute of Technology, Mumbai, India
72
Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany
73
SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS-IN2P3, Nantes, France
74
Yale University, New Haven, CT, USA
75
Budker Institute for Nuclear Physics, Novosibirsk, Russia
76
Oak Ridge National Laboratory, Oak Ridge, TN, USA
77
Physics Department, Creighton University, Omaha, NE, USA
78
Institut de Physique Nucléaire d’Orsay (IPNO), Université Paris-Sud, CNRS-IN2P3, Orsay, France
79
Department of Physicse, University of Oslo, Oslo, Norway
80
Dipartimento di Fisica dell’Università and Sezione INFN, Padova, Italy
81
Sezione INFN, Padova, Italy
82
Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic
83
Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
84
Institute for High Energy Physics, Protvino, Russia
85
Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
86
Pusan National University, Pusan, South Korea
87
Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež u Prahy, Czech Republic
88
Dipartimento di Fisica dell’Università ‘La Sapienza’ and Sezione INFN, Rome, Italy
89
Sezione INFN, Rome, Italy
90
Commissariat à l’Energie Atomique, IRFU, Saclay, France
91
Dipartimento di Fisica ‘E.R. Caianiello’ dell’Università and Sezione INFN, Salerno, Italy
92
California Polytechnic State University, San Luis Obispo, CA, USA
93
Departamento de Física de Partículas and IGFAE, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
94
Universidade de São Paulo (USP), São Paulo, Brazil
95
Russian Federal Nuclear Center (VNIIEF), Sarov, Russia
96
Department of Physics, Sejong University, Seoul, South Korea
97
Yonsei University, Seoul, South Korea
98
Technical University of Split FESB, Split, Croatia
99
V. Fock Institute for Physics, St. Petersburg State University, St. Petersburg, Russia
100
Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, CNRS-IN2P3, Strasbourg, France
101
University of Tokyo, Tokyo, Japan
102
Dipartimento di Fisica dell’Università and Sezione INFN, Trieste, Italy
103
Sezione INFN, Trieste, Italy
104
University of Tsukuba, Tsukuba, Japan
105
Dipartimento di Fisica Sperimentale dell’Università and Sezione INFN, Turin, Italy
106
Sezione INFN, Turin, Italy
107
Institute for Subatomic Physics, Utrecht University, Utrecht, Netherlands
108
Soltan Institute for Nuclear Studies, Warsaw, Poland
109
Warsaw University of Technology, Warsaw, Poland
110
Purdue University, West Lafayette, IN, USA
111
Zentrum für Technologietransfer und Telekommunikation (ZTT), Fachhochschule Worms, Worms, Germany
112
Hua-Zhong Normal University, Wuhan, China
113
Yerevan Physics Institute, Yerevan, Armenia
114
Rudjer Bošković Institute, Zagreb, Croatia
* e-mail: Jurgen.Schukraft@cern.ch
Received:
18
April
2010
Revised:
28
April
2010
Published online:
12
June
2010
Charged-particle production was studied in proton–proton collisions collected at the LHC with the ALICE detector at centre-of-mass energies 0.9 TeV and 2.36 TeV in the pseudorapidity range |η|<1.4. In the central region (|η|<0.5), at 0.9 TeV, we measure charged-particle pseudorapidity density 
for inelastic interactions, and 
for non-single-diffractive interactions. At 2.36 TeV, we find 
for inelastic, and 
for non-single-diffractive collisions. The relative increase in charged-particle multiplicity from the lower to higher energy is 
for inelastic and 
for non-single-diffractive interactions. This increase is consistent with that reported by the CMS collaboration for non-single-diffractive events and larger than that found by a number of commonly used models. The multiplicity distribution was measured in different pseudorapidity intervals and studied in terms of KNO variables at both energies. The results are compared to proton–antiproton data and to model predictions.
© Springer-Verlag / Società Italiana di Fisica, 2010
