Fast nucleon emission as a probe of the momentum dependence of the symmetry potential

Abstract

We investigate the structure of the nonlocal contributions to the potential part of the symmetry term of the nuclear equation of state (EOS). Such momentum dependence of the symmetry potential leads to a splitting of the effective masses of protons and neutrons in asymmetric matter that will directly affect the nucleus-nucleus reaction dynamics. Based on microscopic transport simulations we suggest some rather sensitive observables in collisions of neutron-rich (unstable) ions at intermediate energies. In particular we focus the attention on preequilibrium nucleon emissions. We discuss interesting correlations between the $N/Z$ content of the fast emitted particles and their rapidity or transverse momentum, that show a nice dependence on the prescription used for the effective mass splitting.