Neutrino mean free path in asymmetric nuclear matter at high density

We calculate the neutrino mean free path for neutrino-nucleon scattering in highly asymmetric nuclear matter (N much greater than Z) at densities typical for the core of a neutron star. Nuclear matter is described by means of a relativistic field theory of nucleons coupled to neutral, scalar (sigma), and vector (omega) mesons and to charged vector mesons (rho). The correlation effects induced by the strong interaction of nucleons are taken into account within a self-consistent mean field approximation. The contribution of the exchange terms to the nucleon-nucleon interaction is also included. We present results for physical situations which are expected to occur in the cooling of neutron stars. Exchange terms have the effect of increasing the neutrino mean free path by about 50%.