Equilibration and Out-of-equilibrium Effect in Relativistic Heavy Ion Collisions

The approach of a parton plasma at future heavy ion colliders towards kinetic and chemical equilibrium is considered. A plasma with a self-consistent evolving parton-parton interaction strength is shown to equilibrate better and faster than the usual but inconsistent one with a fixed strength. We explain why as a consequence of this, a parton plasma is a unique kind of many-body system. Because our time evolution scheme does not require the plasma to be in either kind of equilibrium from the outset, out-of-equilibrium effect on particle productions can be revealed. We show this on photon production and discuss the implications on photon as a signal to detect the quark-gluon plasma.