Centrality determination of Pb-Pb collisions at sqrt(sNN) = 2.76 TeV with ALICE

B. Abelev , C. Cheshkov (1) , B. Cheynis (1) , L. Ducroux (1) , J.-Y. Grossiord (1) , Maxime Guilbaud (1) , R. Tieulent (1) , A. Uras (1) , Y. Zoccarato (1) , R. Vernet (2) , I. Belikov (3) , B. Hippolyte (3) , C.C. Kuhn (3) , L. Molnar (3) , C.S. Roy (3) , X. Sanchez Castro (3) , Laurent Aphecetche (4) , Guillaume Batigne (4) , E. Bergognon (4) , M. Bregant (4) , H. Delagrange (4) , O. Driga (4) , B. Erazmus (4) , Magali Estienne (4) , Marie Germain (4) , A. Lardeux (4) , Gines Martinez Garcia (4) , A. Mas (4) , L. Massacrier (4) , Philippe Pillot (4) , Y. Schutz (4) , Alexandre Shabetai (4) , Diego Stocco (4) , N. Arbor (5) , G. Conesa Balbastre (5) , J. Faivre (5) , C. Furget (5) , R. Guernane (5) , S. Kox (5) , J.S. Real (5) , C. Silvestre (5) , Y.W. Baek (6) , V. Barret (6) , N. Bastid (6) , P. Crochet (6) , P. Dupieux (6) , R. Ichou (6) , X. Lopez (6) , F. Manso (6) , M. Marchisone (6) , S. Porteboeuf-Houssais (6) , P. Rosnet (6) , B. Vulpescu (6) , X. Zhang (6) , Z. Conesa Del Valle (7) , I. Das (7) , B. Espagnon (7) , C. Hadjidakis (7) , I. Lakomov (7) , C. Suire (7) , J. D. Tapia Takaki (7) , L. Valencia Palomo (7)

1 IPNL - Institut de Physique Nucléaire de Lyon
2 CC-IN2P3 - Centre de Calcul de l'IN2P3
3 DRS-IPHC - Département Recherches Subatomiques
4 SUBATECH - Laboratoire SUBATECH Nantes
5 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
6 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
7 IPNO - Institut de Physique Nucléaire d'Orsay

This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisions at a center-of-mass energy of 2.76 TeV per colliding nucleon pair with ALICE. The centrality is a key parameter in the study of the properties of QCD matter at extreme temperature and energy density, because it is directly related to the initial overlap region of the colliding nuclei. Geometrical properties of the collision, such as the number of participating nucleons and number of binary nucleon-nucleon collisions, are deduced from a Glauber model with a sharp impact parameter selection, and shown to be consistent with those extracted from the data. The centrality determination provides a tool to compare ALICE measurements with those of other experiments and with theoretical calculations.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]; Physique Nucléaire Expérimentale [nucl-ex]

B. Abelev, C. Cheshkov, B. Cheynis, L. Ducroux, J.-Y. Grossiord, et al.. Centrality determination of Pb-Pb collisions at sqrt(sNN) = 2.76 TeV with ALICE. Physical Review C, 2013, 88, pp.044909. ⟨10.1103/PhysRevC.88.044909⟩. ⟨in2p3-00778545⟩