Nuclear equation of state at high density and the properties of neutron stars

We discuss the relativistic nuclear equation of state (EOS) using a relativistic transport model in heavy-ion collisions. From the baryon flow for Au + Au systems at SIS to AGS energies and above we find that the strength of the vector potential has to be reduced moderately at high density or at high relative momenta to describe the flow data at (1--10)A GeV. We use the same dynamical model to calculate the nuclear EOS and then employ this to calculate the gross structure of a neutron star considering the core to be composed of neutrons with an admixture of protons, electrons, muons, sigmas, and lambdas at zero temperature. We then discuss these gross properties of neutron stars such as maximum mass and radius in contrast to the observational values.