The inclusive transverse response of nuclear matter

The electromagnetic inclusive transverse response of nuclear matter at saturation density is studied within the correlated basis function perturbation theory for momentum transfers q from 300 to 550 MeV/c. The correlation operator includes a Jastrow component, accounting for the short range repulsion, as well as longer range spin, tensor and isospin ones. The Schiavilla- Pandharipande-Riska model for the two-body electromagnetic currents, satisfying the continuity equation with realistic v_14 potentials, is adopted. Currents due to intermediate Delta-isobar excitations, are also included. The global contribution of the two-body currents turns out to be positive and provides an enhancement of the one-body transverse response ranging from about 20% for the lower momenta to about 10% for the higher ones. This finding is in agreement with the Green's Function Monte Carlo studies of the transverse Euclidean response in A=3,4 nuclei and contradicts previous results obtained within the Fermi gas and shell models. The tensor-isospin component of the correlation is found to be the leading responsible for such a behavior. The nuclear matter response is compared to recent experimental data on 40Ca and 56Fe.