Abstract
The theory of the optical potential for proton scattering at intermediate energies is discussed in detail. The first and second order terms of the KMT multiple scattering optical potentials are calculated for proton scattering from light nuclei in the intermediate energy region (135-300MeV). A momentum space method is developed which allows the study of all the nonlocalities of the potential. A practical numerically stable approximate procedure for the treatment of the Coulomb interaction in momentum space calculations is discussed. The accuracy of the method is compared with other prescriptions in the literature and is shown to produce accurate calculations of scattering observables. The first order term of the KMT optical potential is calculated for proton elastic scattering from 16O and 40Ca. Several approximate treatments of this potential are analysed. In particular it is shown that, using a free nucleon-nucleon transition amplitude with energy fixed at half of the incident beam energy, the optimal factorization provides a good approximation to the full folding potential in the description of the elastic scattering observables. The second order corrections to the KMT optical potential for the elastic scattering of protons from 16o are calculated at 135, 200 and 300 MeV incident energies, paying particular importance to the nonlocalities inherent in the potential. It is shown that these nuclear medium effects result in a significant reduction in the proton-target absorption and modifies the elastic scattering wave function in the interior of the nucleus.