RPA response function for quasielastic electron scattering in the relativistic σ-ω model

In the Hartree approximation for the relativistic σ-ω model, the σ-meson dominates the longitudinal response function for quasielastic electron scattering, through the effective mass of the nucleon. In the random phase approximation, however, the effective mass effect is cancelled by the particle-hole correlation due to the σ-meson exchange, and the ω-meson also plays an important role in the response function.