Transport of Heavy Quarks Across Glasma

Abstract

The non-equilibrium quark-gluon system called `glasma', which is dominated by classical chromodynamic fields, is produced at an earliest stage of ultrarelativistic heavy-ion collisions. We address the question of how heavy quarks interact with the glasma in comparison with the equilibrated quark-gluon plasma of the same energy density. For this purpose we derive a Fokker-Planck transport equation of heavy quarks embedded in QCD plasma. We first discuss the equilibrium plasma and then the glasma within the same approach where heavy quarks interact not with the plasma constituents but rather with long wavelength classical fields. We first consider the three schematic models of isotropic glasma and then the simplified model of glasma from ultrarelativistic heavy-ion collisions, where the chromodynamic fields are only along the beam direction. The momentum broadening and collisional energy loss of a test heavy quark are computed and compared to those of the equilibrium plasma of the same energy density.