Importance of Nucleon-Nucleon Scattering in the Interaction of Protons with 197Au at 200 MeV

The reaction 197Au(p,p'p") at an incident energy of 200 MeV is investigated to determine the extent to which the interaction proceeds by means of an initial quasi-free nucleon-nucleon mechanism. In strong contrast with some earlier inclusive (p, p') studies, which pointed to a negligible contribution from such a process, we find a large proportion of the reaction yield to originate from a single scattering mechanism in which the struck nucleon undergoes further rescattering. It is found that the characteristic features of quasi-free scattering are not destroyed by multiple-scattering effects in a target nucleus even as massive as 197Au.