Effective interactions for nucleon scattering off isospin-asymmetric targets

We have investigated the role of isospin asymmetry of the nucleon-nucleon NN effective interaction in the context of nucleon-nucleus NA elastic scattering. To this purpose we assume that the in-medium g matrix is an admixture of isospin-symmetric nuclear matter and pure neutron matter solutions of Brueckner-Hartree-Fock equations, denoted as g[ρ,β]. The isospin-asymmetric g matrices are then used for the construction of optical potentials for elastic nucleon scattering from closed-shell nuclei. The calculated optical potentials [based on the Argonne v₁₈ NN interaction] is nonlocal and energy-dependent. We have found that the inclusion of isospin asymmetry in the g matrix, in the context of the δg folding, yields a reasonable description of differential cross sections for ⁴⁸Ca and ²⁰⁸Pb at nucleon beam energies between 40 and 100 MeV. For energies at and below 65 MeV the δg folding including neutronic matter g matrices yield better agreement with the data relative to its approximations.