Centrality and transverse momentum dependence of J/ψ production in Pb-Pb collisions at √SNN = 5.02 TeV at mid-rapidity with ALICE

Dennis Weiser

doi:10.1051/epjconf/201817118018

Abstract

We present new results for the nuclear modification factor RAA of J/ψ mesons as a function of centrality and transverse momentum at mid-rapidity. The measurement is carried out with the ALICE central barrel detectors in the acceptance range |y| < 0.9 and pT > 0 in the dielectron decay channel.

Highlights

The measurement of J/ψ production is a key measurement to study deconfinement in nucleus-nucleus collisions
The nuclear modification factor RAA for J/ψ mesons is obtained as a function of centrality, rapidity and transverse momentum
For the mid-rapidity measurement the J/ψ candidates with pT < 150 MeV have been excluded to avoid a contamination with photoproduced J/ψ’s which mostly play a role in peripheral collisions

Summary

Introduction

The measurement of J/ψ production is a key measurement to study deconfinement in nucleus-nucleus collisions. The initial idea was that the high color density in the medium prevents the formation of charmonia [1]. This would be observable as a suppression of the yield of J/ψ mesons in AA collisions compared to pp collisions scaled to binary nucleon-nucleon collisions. At higher center-of-mass energies at the LHC the additional production of J/ψ mesons via the (re)combination of ccquarks is possible due to the increasing charm cross section σcc. The data from the LHC Run 1, taken at a collision energy of. √thseNNdiff=e5re.0n2t model sceTeV in the LHC Run 2 provide further insights to the possible production mechanisms, due to more precise and differential measurements enabled by the higher available statistics

Analysis

Results

Conclusions