Jet quenching in glasma

Abstract

We discuss the transverse momentum broadening of hard probes traversing an evolving glasma, which is the earliest phase of the matter produced in relativistic heavy-ion collisions. The coefficient $\hat{q}$ is calculated using the Fokker-Planck equation, and an expansion in the proper time $\tau$ which is applied to describe the temporal evolution of the glasma. The correlators of the chromodynamic fields that determine the Fokker-Planck collision term, which in turn provides $\hat{q}$, are computed to fifth order in $\tau$. The momentum broadening is shown to rapidly grow in time and reach a magnitude of several $\mathrm{Ge}{\mathrm{V}}^2/fm$. We show that the transient pre-equilibrium phase provides a contribution to the energy loss of hard probes which is comparable to that of the long lasting, hydrodynamically evolving, equilibrium phase.

Comments: 5 pages, 3 figures, estimate of gauge dependence included, final version