Centrality dependence of inclusive J/$\psi$ production in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

J. Adam , Laurent Aphecetche (1) , B. Audurier (1) , A. Baldisseri (2) , Guillaume Batigne (1) , I. Belikov (3) , H. Borel (2) , J. Castillo Castellanos (2) , J.L. Charvet (2) , C. Cheshkov (4) , B. Cheynis (4) , L. Ducroux (4) , Magali Estienne (1) , Marie Germain (1) , J.-Y. Grossiord (4) , B. Hippolyte (3) , A. Lardeux (2) , J. Martin Blanco (1) , Gines Martinez Garcia (1) , L. Massacrier (1) , L. Molnar (3) , D.A. Moreira De Godoy (1) , A. Morreale (1) , H. Pereira Da Costa (2) , Philippe Pillot (1) , F. Rami (3) , L. Ronflette (1) , C. Roy (3) , X. Sanchez Castro (3) , Alexandre Shabetai (1) , Diego Stocco (1) , B. Teyssier (4) , R. Tieulent (4) , A. Uras (4) , R. Vernet (5) , M. Wang (1) , G. Conesa Balbastre (6) , J. Faivre (6) , C. Furget (6) , R. Guernane (6) , J.S. Real (6) , C. Silvestre (6) , A. Vauthier (6) , Z. Conesa Del Valle (7) , I. Das , B. Espagnon (7) , C. Hadjidakis (7) , I. Lakomov (7) , C. Suire (7) , J. D. Tapia Takaki (7) , M. Tarhini (7) , L. Valencia Palomo (7)

1 SUBATECH - Laboratoire SUBATECH Nantes
2 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
3 IPHC - Institut Pluridisciplinaire Hubert Curien
4 IPNL - Institut de Physique Nucléaire de Lyon
5 CC-IN2P3 - Centre de Calcul de l'IN2P3
6 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
7 IPNO - Institut de Physique Nucléaire d'Orsay

We present a measurement of inclusive J/$\psi$ production in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV as a function of the centrality of the collision, as estimated from the energy deposited in the Zero Degree Calorimeters. The measurement is performed with the ALICE detector down to zero transverse momentum, $p_{\rm T}$, in the backward ($-4.46 < y_{\rm cms} < -2.96$) and forward ($2.03 < y_{\rm cms} < 3.53$) rapidity intervals in the dimuon decay channel and in the mid-rapidity region ($-1.37 < y_{\rm cms} < 0.43$) in the dielectron decay channel. The backward and forward rapidity intervals correspond to the Pb-going and p-going direction, respectively. The $p_{\rm T}$-differential J/$\psi$ production cross section at backward and forward rapidity is measured for several centrality classes, together with the corresponding average $p_{\rm T}$ and $p^2_{\rm T}$ values. The nuclear modification factor, $Q_{\rm pPb}$, is presented as a function of centrality for the three rapidity intervals, and, additionally, at backward and forward rapidity, as a function of $p_{\rm T}$ for several centrality classes. At mid- and forward rapidity, the J/$\psi$ yield is suppressed up to 40% compared to that in pp interactions scaled by the number of binary collisions. The degree of suppression increases towards central p-Pb collisions at forward rapidity, and with decreasing $p_{\rm T}$ of the J/$\psi$. At backward rapidity, the $Q_{\rm pPb}$ is compatible with unity within the total uncertainties, with an increasing trend from peripheral to central p-Pb collisions.

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

J. Adam, Laurent Aphecetche, B. Audurier, A. Baldisseri, Guillaume Batigne, et al.. Centrality dependence of inclusive J/$\psi$ production in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. Journal of High Energy Physics, 2015, 11, pp.127. ⟨10.1007/JHEP11(2015)127⟩. ⟨in2p3-01169682⟩