Relativistic meson exchange and isobar currents in electron scattering: Noninteracting Fermi gas analysis

Abstract

We study two-body currents in the noninteracting relativistic Fermi gas model. Special emphasis is put on the role of the \ensuremath{\Delta} isobar. Due to a resonance behavior, relativistic two-body isobar currents are found to be important in comparison with experimental data. Real-pion production is studied within the same framework, and the importance and physical implications of the energy dependence of the \ensuremath{\Delta}-isobar decay width are stressed.