TEMPERATURE-DEPENDENT MEAN-FIELD AND ITS EFFECT ON HEAVY-ION REACTIONS

Temperature-dependent mean field potentials of nucleons are obtained b y solving the Bethe-Goldstone equation for a realistic force in nuclea r matter at finite temperature. For a more efficient utilization of th ese potentials in studying the heavy-ion reactions using a transport t heory, the density and temperature dependence of these potentials is p arametrized in a Skyrme type form. These parametrized temperature-depe ndent potentials are implemented in quantum molecular dynamics. The te mperature during the simulations is deduced using a hot Thomas-Fermi a pproach generalized for the case of two interpenetrating pieces of nuc lear matter. First of all, we show that our formalism works well in th e nuclear matter limit. In order to study the effect of temperature de pendence in the mean-field potential in heavy-ion reactions, the react ions Ca-40 + Ca-40 and Nb-93 + Nb-93 are simulated using both a finite temperature-dependent potential and a temperature-independent (i.e. z ero temperature) potential. Our detailed investigation shows that the temperature dependence of the mean field affects the heavy-ion reactio n dynamics to a significant amount. These effects are stronger in case of heavier nuclei and are of the same order as the differences betwee n the usual ''soft'' and ''hard'' equation of state. An analytical par ametrization of the temperature dependence of the self-consistent fiel d is given in a Skyrme type form.