Nonlocal Velocity-Dependent Optical Potential and the Perey Effect: The Incident Proton Case

In the nucleus interior, the presence of a nonlocal potential leads to suppression or enhancement of the wave functions that differ from the corresponding wave functions obtained by a local potential. This is known as the Perey effect. In this work, we utilize the calculated Perey damping factor to demonstrate that the nonlocal velocity-dependent optical potential simulates a source of nonlocality. In that regard, we considered proton scattering from 12C, 16O, 40Ca, 58Ni, and 120Sn in the energy range between 10–40 MeV. The Perey damping factor is calculated for each nucleus at each incident proton energy and for different angular momentum quantum numbers to assess the nonlocality strength resulting from the velocity-dependent nonlocal optical potential. The potential parameters required to determine the local and the nonlocal wave functions, and therefore the Perey damping factors, are obtained from different articles. In one case, the required potential parameters were obtained by fitting these parameters to the experimental angular distributions using a least-square fit analysis. Our results demonstrate that the effect of the nonlocal potential is dependent on the target and is dependent on both energy and orbital angular momentum for each target.