Final-state interaction in inclusive electromagnetic nuclear processes

The problem of nucleon final-state interaction in inclusive electromagnetic reactions is discussed within an optical potential description for the outgoing nucleon. The formalism accounts for both the loss of flux in the primary one-nucleon removal channel and the excitation of the multinucleon ones. Thereby a crucial difficulty encountered in the distorted-wave Born-approximation treatments of inclusive processes is eliminated. The calculation has been applied to the ($e, e^{\prime }$) reaction at the Stanford kinematics of 500 MeV incident energy and 60° scattering angle. As a result of nucleon final-state interaction, the peak intensities are reduced by 5-10%; about half of the ($e, e^{\prime }$) reaction is found to correspond to multinucleon removal. In contrast to the good agreement of the calculation with the Stanford data, severe discrepancies are obtained if applied to the recent Saclay data for incident energies around 400 MeV. The limitations of our approach are explored by considering processes at relatively low momentum transfers: low-energy electron scattering and radiative pion capture.