J/$\psi$ suppression at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

TL;DR

This paper reports on the measurement of J/ψ suppression at forward rapidity in Pb-Pb collisions at 2.76 TeV, revealing significant suppression patterns that differ from lower energy results and are consistent with models involving deconfined charm quarks.

Contribution

First measurement of inclusive J/ψ production at forward rapidity in Pb-Pb collisions at 2.76 TeV down to zero transverse momentum, providing new insights into quark-gluon plasma effects.

Findings

J/ψ suppression observed with nuclear modification factor ~0.55

Suppression does not significantly depend on collision centrality

Results align with models including charm quark production in deconfined phase

Abstract

The ALICE experiment has measured the inclusive J/$\psi$ production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}} } = 2.76$ TeV down to zero transverse momentum in the rapidity range $2.5 < y < 4$. A suppression of the inclusive J/$\psi$ yield in Pb-Pb is observed with respect to the one measured in pp collisions scaled by the number of binary nucleon-nucleon collisions. The nuclear modification factor, integrated over the 0-80% most central collisions, is $0.545 \pm 0.032 \rm{(stat.)} \pm 0.083 \rm{(syst.)}$ and does not exhibit a significant dependence on the collision centrality. These features appear significantly different from measurements at lower collision energies. Models including J/$\psi$ production from charm quarks in a deconfined partonic phase can describe our data.