Charmonia suppression in heavy ion collisions: Hot versus cold matter effects

In this paper we study charmonium suppression in heavy ion collisions and develop a joint microscopic description of the initial- and final-state interactions. In the cold phase, we consider a conventional mechanism of nuclear suppression due to inelastic absorptive interactions. We also take into account a novel production mechanism via fusion of three gluons from different nucleons, which partially compensates the strong suppression of the first term expected in the Large Hadron Collider (LHC) kinematics. In the hot phase, we take into account both the Debye screening and the absorptive correction due to color-exchange interactions with the medium. We found that the latter mechanism becomes dominant for large transverse momenta $\ensuremath{\langle}{p}_{T}\ensuremath{\rangle}\ensuremath{\gtrsim}10\phantom{\rule{0.28em}{0ex}}\mathrm{GeV}$. The evaluated suppression ${R}_{AA}$ in our approach is in reasonable agreement with recent experimental data for $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)$ in the LHC kinematics.

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