MEAN FIELDS IN COLLIDING NUCLEAR-MATTER

The momentum-space configuration of the participant nucleons in the ea rly stage of heavy-ion collisions can be described by a colliding nucl ear matter configuration, i.e. by two Lorentz elongated Fermi ellipsoi ds. We introduce this configuration in the framework of the Hartree ap proximation of the sigma omega-model. The configuration and the mean f ields are constructed self-consistently, respecting the Pauli principl e for interpenetrating ellipsoids at low relative velocity in a covari ant and density conserving manner. In a second step we approximately c onstruct mean fields for these configurations in the context of Brueck ner theory. To do this we parametrize the real part of the self-energy of relativistic Brueckner calculations for equilibrated nuclear matte r (one-Fermi sphere) in a Hartree scheme to obtain momentum- and densi ty-dependent coupling parameters. With these we calculate the scalar a nd vector self-energy of a nucleon in colliding nuclear matter consist ently with the configuration. The mean self-energy components show str ong correlation and exchange effects. The results can be used to impro ve relativistic transport calculations for heavy-ion collisions.