Mean field description of electron induced quasi-elastic excitation in nuclei

Abstract

The validity of the approximations done in the mean field description of the quasi-elastic excitation of medium-heavy nuclei is discussed. A test of the reliability of the plane wave Born approximation is presented. The uncertainty related to the choice of the electromagnetic nucleon form factors is discussed. The effects produced by the meson exchange currents generated by the exchange of a single pion are studied, as well as the need of including relativistic corrections to the one-body currents. The results of the continuum shell model and those of the Fermi gas model are compared and the need of treating the emitted nucleon within a relativistic framework is studied. We analyze the results of Random Phase Approximation calculations not only in terms of their effects on the mean field responses, but also in terms of the theoretical consistency in the choice of the effective residual interaction. The role of the final state interaction is investigated. A microscopic justification of the use of complex optical potential to describe the final state interaction is provided. The effects of the final state interaction on the mean field responses are studied with a sum rule conserving model. A comparison with the experimental data measured in the C12 and Ca40 nuclei is shown.