Effects of meson-exchange currents on the $(\protect\vec{e},e'p)$ structure functions

Abstract

The response functions for the unpolarized $(e,e^{\prime }p)$ and polarized $(\vec{e},e^{\prime }p)$ reaction are calculated for medium-heavy nuclei under quasifree conditions. The formalism presented here incorporates two-body currents related to meson-exchange and the $\Delta (1232)$ excitation. The final-state interaction of the outgoing nucleon with the residual nucleus is handled in a HF-RPA formalism. The sensitivity of the results to the two-body currents is discussed for the five structure functions in quasielastic $(\vec{e},e^{\prime }p)$ scattering off the target nuclei ${}^{16}O$ and ${}^{40}Ca$. A selective sensitivity to the two-body currents is obtained in the longitudinal-transverse interference term $W_{LT}$ where two-body currents can explain part of the discrepancy between the impulse-approximation calculations and the data.

12 pages in LaTex with 5 figures (available on request), INW0703