Quarkonia Measurements with ALICE at the LHC

TL;DR

This paper presents ALICE experiment measurements of quarkonia production in proton-proton and lead-lead collisions at the LHC, providing insights into quark-gluon plasma properties and quarkonium production models.

Contribution

First high-precision measurements of J/psi production cross sections and nuclear modification factors in LHC collisions, serving as a baseline for QGP studies.

Findings

J/psi transverse momentum and rapidity distributions measured at 7 and 2.76 TeV.

J/psi yield dependence on charged particle multiplicity analyzed.

Nuclear modification factor R_AA and R_CP for J/psi in Pb-Pb collisions reported.

Abstract

ALICE is the dedicated heavy-ion experiment at the Large Hadron Collider (LHC). It is designed to provide excellent capabilities to study the quark-gluon plasma (QGP) in the highest energy density regime opened up by the LHC. Quarkonia are crucial probes of the QGP. High-precision data from pp collisions are an essential baseline, and serve as a crucial test for competing models of quarkonium hadroproduction. ALICE measures quarkonia down to pt=0 via their decay channels into e+e- at central (|y|<0.9) and into mu+mu- at forward rapidity (-4.0<y<-2.5). We present first results on the transverse momentum and rapidity distributions of the inclusive J/psi production cross section in sqrt(s)=7 and 2.76 TeV pp collisions. The dependence of the J/psi yield on the charged particle multiplicity in sqrt(s)=7 TeV pp collisions is discussed. Finally, results on the inclusive J/psi production in sqrt(s_NN)=2.76 TeV Pb-Pb collisions, the nuclear modification factor R_AA and the central-to-peripheral modification factor R_CP are shown.