Effects of two-body currents in the one-particle one-hole electromagnetic responses within a relativistic model

Abstract Longitudinal ( R L ) and transverse ( R T ) responses from inclusive electron scattering from 12 C and 40 Ca nuclei are computed within a fully relativistic model, and one- and two-body current operators leading to a final one-particle one-hole state. We find that the two-body contributions have no effect on R L but they increase R T by up to 30%, depending on the energy and momentum transfer. Inclusive cross sections have also been computed, obtaining an increase which depends on the degree of transversity of each kinematic. The comparison with carbon data is good for the responses and the cross sections. In the case of calcium, while the model compares well with the cross section data, the agreement with the responses is generally poor. However, the inconsistencies between different data sets for the separate responses in this nucleus indicate that uncertainties in the responses are largely underestimated in the data. Our calculation is fully relativistic, does not require a factorized model and includes a full quantum mechanical description of both the initial and final nucleon states. We also show that incorporating the distortion of the nucleons while making the initial and final states orthogonal is essential to reproduce the shape and magnitude of the cross section data and carbon responses. The good agreement with the electron scattering experimental data supports the use of this approach to describe the analogous neutrino-induced scattering reaction.