pQCD approach to Charmonium regeneration in QGP at the LHC

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
Comment: 20 pages, 15 figures; Accepted for publication in Nuclear Physics A