Dynamical evolution of the scalar condensate in heavy ion collisions

We derive the effective coarse-grained field equation for the scalar condensate of the linear sigma model in a simple and straightforward manner using linear response theory. The dissipative coefficient is calculated consistently at tree level on the basis of the physical processes of sigma-meson decay and of thermal sigma mesons and pions knocking sigma mesons out of the condensate. The field equation is solved for hot matter undergoing either one- or three-dimensional expansion and cooling in the aftermath of a high energy nuclear collision. The results show that the time constant for returning the scalar condensate to thermal equilibrium is of order [Formula Presented].