Quasielastic electron scattering on 12C and 40Ca in the relativistic Hartree approximation Relativistic corrections to the response functions

Abstract

The quenching of the longitudinal response functions observed in high-energy electron scattering is studied within a self-consistent relativistic Hartree approximation in the σ-ω model. The σ-ω model yields a small nucleon effective mass which reduces the response functions around the peak position through the Perey effect and the relativistic nuclear current. This reduction, however, is partially cancelled by effects from the relativistic kinematics. Consequently, the reduction is not enough to explain the quenching phenomena of the longitudinal response functions around the peak. The relativistic Coulomb sum values, on the other hand, are little reduced, compared with those of nonrelativistic models, failing to reproduce experimental data. In contrast to the longitudinal ones, the transverse response functions around the peak are enhanced by relativistic effects on the nuclear current. Nevertheless, the present model underestimates experimental values at high momentum transfer.