Many-Body Effects in the (e, e′p) Reaction

We present the first quantitative study of the final-state-interaction effect in the missing-energy spectrum measured in a coincidence ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(e, e^{\prime }p)$ experiment in the dip region. It is found that the calculated cross section for the two-body type of final-state interaction is very small compared with the data. Furthermore, it decreases with increasing missing energy; this qualitative behavior does not agree with the data. From a qualitative investigation, the presence of the many-body mechanism involving more than two nucleons is suggested.