Elsevier

Physics Letters B

Volume 696, Issues 1–2, 24 January 2011, Pages 30-39
Physics Letters B

Suppression of charged particle production at large transverse momentum in central Pb–Pb collisions at sNN=2.76 TeV

https://doi.org/10.1016/j.physletb.2010.12.020Get rights and content
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Abstract

Inclusive transverse momentum spectra of primary charged particles in Pb–Pb collisions at sNN=2.76TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0–5% and 70–80% of the hadronic Pb–Pb cross section. The measured charged particle spectra in |η|<0.8 and 0.3<pT<20GeV/c are compared to the expectation in pp collisions at the same sNN, scaled by the number of underlying nucleon–nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAA. The result indicates only weak medium effects (RAA0.7) in peripheral collisions. In central collisions, RAA reaches a minimum of about 0.14 at pT=67GeV/c and increases significantly at larger pT. The measured suppression of high-pT particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb–Pb collisions at the LHC.

Keywords

RAA
Nuclear modification factor
Pb–Pb
sNN=2.76TeV
ALICE
LHC

Cited by (0)

© CERN, for the benefit of the ALICE Collaboration.

1

Also at Laboratoire de Physique Corpusculaire (LPC), Clermont Université, Université Blaise Pascal, CNRS–IN2P3, Clermont-Ferrand, France.

2

Now at Centro Fermi – Centro Studi e Ricerche e Museo Storico della Fisica “Enrico Fermi”, Rome, Italy.

3

Now at Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany.

4

Now at Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany.

5

Now at Sezione INFN, Turin, Italy.

6

Now at University of Houston, Houston, TX, United States.

7

Also at Dipartimento di Fisica dell'Università, Udine, Italy.

8

Now at SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS–IN2P3, Nantes, France.

9

Now at Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City and Mérida, Mexico.

11

Now at Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier, CNRS–IN2P3, Institut Polytechnique de Grenoble, Grenoble, France.

12

Now at Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, CNRS–IN2P3, Strasbourg, France.

13

Now at Sezione INFN, Padova, Italy.

14

Deceased.

15

Also at Division of Experimental High Energy Physics, University of Lund, Lund, Sweden.

16

Also at University of Technology and Austrian Academy of Sciences, Vienna, Austria.

17

Also at European Organization for Nuclear Research (CERN), Geneva, Switzerland.

18

Now at Oak Ridge National Laboratory, Oak Ridge, TN, United States.

19

Now at European Organization for Nuclear Research (CERN), Geneva, Switzerland.

20

Also at Wayne State University, Detroit, MI, United States.

21

Also at Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany.

22

Now at Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany.

23

Also at Fachhochschule Köln, Köln, Germany.

24

Also at Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovakia.

25

Now at Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico.

26

Also at Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier, CNRS–IN2P3, Institut Polytechnique de Grenoble, Grenoble, France.

27

Also at “Vinča” Institute of Nuclear Sciences, Belgrade, Serbia.

28

Also at University of Houston, Houston, TX, United States.

29

Also at Department of Physics, University of Oslo, Oslo, Norway.

30

Also at Variable Energy Cyclotron Centre, Kolkata, India.

31

Now at Department of Physics, University of Oslo, Oslo, Norway.

32

Also at Dipartimento Interateneo di Fisica ‘M. Merlin’ and Sezione INFN, Bari, Italy.

33

Now at Nikhef, National Institute for Subatomic Physics and Institute for Subatomic Physics of Utrecht University, Utrecht, Netherlands.

34

Also at Hua-Zhong Normal University, Wuhan, China.

35

Also at Centro Fermi – Centro Studi e Ricerche e Museo Storico della Fisica “Enrico Fermi”, Rome, Italy.