PROPERTIES OF DENSE MATTER IN A SUPERNOVA CORE IN THE RELATIVISTIC MEAN-FIELD THEORY

We have used the Zimanyi & Moszkowski model in the relativistic mean-f ield theory to study the properties of asymmetric nuclear matter and t he equation of state (EOS) for supernova matter. We find that even tho ugh muons are included in the chemical composition of neutron-star mat ter, this model still results in a small proton concentration so that only the modified Urea process occurs as a main neutrino reaction in n eutron stars. This conclusion is opposite to that of the previous stud ies in the relativistic mean-field theory. The incompressibility of sy mmetric nuclear matter is consistent with both the experimental values extracted from the nuclear physics and the constraints placed on the EOS by observations of neutron star masses. If the EOS for supernova m atter is described by this model, the prompt mechanism for Type II sup ervovae cannot work, but the EOS is likely to be favourable to the del ayed explosion mechanism.