Initial conditions for hydrodynamics from kinetic theory equilibration

Abstract

We use effective kinetic theory to study the pre-equilibrium dynamics in heavy-ion collisions. We describe the evolution of linearized energy perturbations on top of out-of-equilibrium background to the energy-momentum tensor at a time when hydrodynamics becomes applicable. We apply this description to IP-Glasma initial conditions and find an overall smooth transition to hydrodynamics. In a phenomenologically favorable range of $\eta /s$ values, early time dynamics can be accurately described in terms of a few functions of a scaled time variable $\tau T/(\eta /s)$. Our framework can be readily applied to other initial state models to provide the pre-equilibrium dynamics of the energy momentum tensor.

Comments: 5 pages, 5 figures, Proceedings for the 26th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2017), February 5-11 2017, Chicago, Illinois, USA