https://doi.org/10.1140/epjc/s10052-013-2617-1
Regular Article - Experimental Physics
Charmonium and e
+
e
− pair photoproduction at mid-rapidity in ultra-peripheral Pb–Pb collisions at
1
CERN, 1211, Geneva 23, Switzerland
2
Academy of Scientific Research and Technology (ASRT), Cairo, Egypt
3
A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation, Yerevan, Armenia
4
Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
5
Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine
6
Department of Physics and Centre for Astroparticle Physics and Space Science (CAPSS), Bose Institute, Kolkata, India
7
Budker Institute for Nuclear Physics, Novosibirsk, Russia
8
California Polytechnic State University, San Luis Obispo, California, United States
9
Central China Normal University, Wuhan, China
10
Centre de Calcul de l’IN2P3, Villeurbanne, France
11
Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Havana, Cuba
12
Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
13
Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City and Mérida, Mexico
14
Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Rome, Italy
15
Chicago State University, Chicago, United States
16
Commissariat à l’Energie Atomique, IRFU, Saclay, France
17
COMSATS Institute of Information Technology (CIIT), Islamabad, Pakistan
18
Departamento de Física de Partículas and IGFAE, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
19
Department of Physics, Aligarh Muslim University, Aligarh, India
20
Department of Physics and Technology, University of Bergen, Bergen, Norway
21
Department of Physics, Ohio State University, Columbus, Ohio, United States
22
Department of Physics, Sejong University, Seoul, South Korea
23
Department of Physics, University of Oslo, Oslo, Norway
24
Dipartimento di Fisica dell’Università and Sezione INFN, Trieste, Italy
25
Dipartimento di Fisica dell’Università and Sezione INFN, Cagliari, Italy
26
Dipartimento di Fisica dell’Università and Sezione INFN, Turin, Italy
27
Dipartimento di Fisica dell’Università ‘La Sapienza’ and Sezione INFN, Rome, Italy
28
Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Catania, Italy
29
Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Bologna, Italy
30
Dipartimento di Fisica e Astronomia dell’Università and Sezione INFN, Padova, Italy
31
Dipartimento di Fisica ‘E.R. Caianiello’ dell’Università and Gruppo Collegato INFN, Salerno, Italy
32
Dipartimento di Scienze e Innovazione Tecnologica dell’Università del Piemonte Orientale and Gruppo Collegato INFN, Alessandria, Italy
33
Dipartimento Interateneo di Fisica ‘M. Merlin’ and Sezione INFN, Bari, Italy
34
Division of Experimental High Energy Physics, University of Lund, Lund, Sweden
35
European Organization for Nuclear Research (CERN), Geneva, Switzerland
36
Fachhochschule Köln, Köln, Germany
37
Faculty of Engineering, Bergen University College, Bergen, Norway
38
Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
39
Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic
40
Faculty of Science, P.J. Šafárik University, Košice, Slovakia
41
Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
42
Gangneung-Wonju National University, Gangneung, South Korea
43
Department of Physics, Gauhati University, Guwahati, India
44
Helsinki Institute of Physics (HIP) and University of Jyväskylä, Jyväskylä, Finland
45
Hiroshima University, Hiroshima, Japan
46
Indian Institute of Technology Bombay (IIT), Mumbai, India
47
Indian Institute of Technology Indore (IITI), Indore, India
48
Institut de Physique Nucléaire d’Orsay (IPNO), Université Paris-Sud, CNRS-IN2P3, Orsay, France
49
Institute for High Energy Physics, Protvino, Russia
50
Institute for Nuclear Research, Academy of Sciences, Moscow, Russia
51
Nikhef, National Institute for Subatomic Physics and Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands
52
Institute for Theoretical and Experimental Physics, Moscow, Russia
53
Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovakia
54
Institute of Physics, Bhubaneswar, India
55
Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
56
Institute of Space Sciences (ISS), Bucharest, Romania
57
Institut für Informatik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
58
Institut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
59
Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Germany
60
Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany
61
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
62
Instituto de Física, Universidad Nacional Autónoma de México, Mexico City, Mexico
63
Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, CNRS-IN2P3, Strasbourg, France
64
Joint Institute for Nuclear Research (JINR), Dubna, Russia
65
Kirchhoff-Institut für Physik, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
66
Korea Institute of Science and Technology Information, Daejeon, South Korea
67
KTO Karatay University, Konya, Turkey
68
Laboratoire de Physique Corpusculaire (LPC), Clermont Université, Université Blaise Pascal, CNRS–IN2P3, Clermont-Ferrand, France
69
Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier, CNRS-IN2P3, Institut Polytechnique de Grenoble, Grenoble, France
70
Laboratori Nazionali di Frascati, INFN, Frascati, Italy
71
Laboratori Nazionali di Legnaro, INFN, Legnaro, Italy
72
Lawrence Berkeley National Laboratory, Berkeley, California, United States
73
Lawrence Livermore National Laboratory, Livermore, California, United States
74
Moscow Engineering Physics Institute, Moscow, Russia
75
National Centre for Nuclear Studies, Warsaw, Poland
76
National Institute for Physics and Nuclear Engineering, Bucharest, Romania
77
National Institute of Science Education and Research, Bhubaneswar, India
78
Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
79
Nikhef, National Institute for Subatomic Physics, Amsterdam, Netherlands
80
Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež u Prahy, Czech Republic
81
Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States
82
Petersburg Nuclear Physics Institute, Gatchina, Russia
83
Physics Department, Creighton University, Omaha, Nebraska, United States
84
Physics Department, Panjab University, Chandigarh, India
85
Physics Department, University of Athens, Athens, Greece
86
Physics Department, University of Cape Town and iThemba LABS, National Research Foundation, Somerset West, South Africa
87
Physics Department, University of Jammu, Jammu, India
88
Physics Department, University of Rajasthan, Jaipur, India
89
Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
90
Politecnico di Torino, Turin, Italy
91
Purdue University, West Lafayette, Indiana, United States
92
Pusan National University, Pusan, South Korea
93
Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
94
Rudjer Bošković Institute, Zagreb, Croatia
95
Russian Federal Nuclear Center (VNIIEF), Sarov, Russia
96
Russian Research Centre Kurchatov Institute, Moscow, Russia
97
Saha Institute of Nuclear Physics, Kolkata, India
98
School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom
99
Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Lima, Peru
100
Sezione INFN, Catania, Italy
101
Sezione INFN, Turin, Italy
102
Sezione INFN, Padova, Italy
103
Sezione INFN, Bologna, Italy
104
Sezione INFN, Cagliari, Italy
105
Sezione INFN, Trieste, Italy
106
Sezione INFN, Bari, Italy
107
Sezione INFN, Rome, Italy
108
Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, United Kingdom
109
SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS-IN2P3, Nantes, France
110
Suranaree University of Technology, Nakhon Ratchasima, Thailand
111
Technical University of Split FESB, Split, Croatia
112
Technische Universität München, Munich, Germany
113
The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
114
Physics Department, The University of Texas at Austin, Austin, TX, United States
115
Universidad Autónoma de Sinaloa, Culiacán, Mexico
116
Universidade de São Paulo (USP), São Paulo, Brazil
117
Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
118
Université de Lyon, Université Lyon 1, CNRS/IN2P3, IPN-Lyon, Villeurbanne, France
119
University of Houston, Houston, Texas, United States
120
University of Technology and Austrian Academy of Sciences, Vienna, Austria
121
University of Tennessee, Knoxville, Tennessee, United States
122
University of Tokyo, Tokyo, Japan
123
University of Tsukuba, Tsukuba, Japan
124
Eberhard Karls Universität Tübingen, Tübingen, Germany
125
Variable Energy Cyclotron Centre, Kolkata, India
126
Vestfold University College, Tonsberg, Norway
127
V. Fock Institute for Physics, St. Petersburg State University, St. Petersburg, Russia
128
Warsaw University of Technology, Warsaw, Poland
129
Wayne State University, Detroit, Michigan, United States
130
Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary
131
Yale University, New Haven, Connecticut, United States
132
Yildiz Technical University, Istanbul, Turkey
133
Yonsei University, Seoul, South Korea
134
Zentrum für Technologietransfer und Telekommunikation (ZTT), Fachhochschule Worms, Worms, Germany
* e-mail: Eugenio.Scapparone@bo.infn.it
Received:
8
May
2013
Revised:
19
August
2013
Published online:
9
November
2013
The ALICE Collaboration at the LHC has measured the J/ψ and ψ′ photoproduction at mid-rapidity in ultra-peripheral Pb–Pb collisions at .
The charmonium is identified via its leptonic decay for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 23 μb−1. The cross section for coherent and incoherent J/ψ production in the rapidity interval −0.9<y<0.9, are and
, respectively. The results are compared to theoretical models for J/ψ production and the coherent cross section is found to be in good agreement with those models incorporating moderate nuclear gluon shadowing at Bjorken-x around 10−3, such as EPS09 parametrization. In addition the cross section for the process γγ→e
+
e
− has been measured and found to be in agreement with models implementing QED at leading order.
© Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica, 2013