pQCD approach to Charmonium regeneration in QGP at the LHC

TL;DR

This paper applies perturbative QCD to model charmonium regeneration in quark-gluon plasma at the LHC, calculating recombination cross sections and comparing suppression patterns with experimental data.

Contribution

It introduces a temperature-dependent pQCD framework with coupled rate equations to analyze charmonium formation and suppression in QGP, incorporating various medium effects.

Findings

Recombination cross sections increase with temperature.

Model predictions agree with ALICE and CMS suppression data.

Temperature-dependent formation times improve accuracy.

Abstract

We analyze the applicability of perturbative QCD (pQCD) approach to the issue of $J/\psi$ recombination at the Large Hadron Collider (LHC), and calculate the recombination cross section for $c\bar{c}$ recombination to form $J/\psi$ as a function of temperature. The charmonium wavefunction is obtained by employing a temperature dependent phenomenological potential between the $c\bar{c}$ pair. The temperature dependent formation time of charmonium is also employed in the current work. A set of coupled rate equations is established which incorporates color screening, gluonic dissociation, collisional damping and recombination of uncorrelated $c\bar{c}$ pair in the quark-gluon plasma (QGP) medium. The final $J/\psi$ suppression, thus determined as a function of centrality is compared with the ALICE experimental data at both mid and forward rapidity and CMS experimental data at mid rapidity obtained from the Large Hadron Collider (LHC) at center of mass energy $\sqrt{s_{NN}} = 2.76$ TeV. Keywords : Color screening, Recombination, Gluonic dissociation, Collisional damping, Survival probability, pQCD, Charmonium PACS numbers : 12.38.Mh, 12.38.Gc, 25.75.Nq, 24.10.Pa