Nonrelativistic full-folding model of nucleon elastic scattering at intermediate energies

Abstract

Nonrelativistic full-folding optical model potentials for nucleon elastic scattering have been calculated and applied to proton scattering on ' 0 and Ca at energies between 135 and 500 MeV. The optical potentials were calculated in momentum space by folding the mixed target density with the off-energy-shell free t matrix derived from the Paris nucleon-nucleon potential. The energy dependence and knockon exchange terms of the t matrix were included explicitly. Significant differences were observed between observables calculated from the full-folding model and conventional tp approximations to it. At proton energies near and below -400 MeV, the full-folding model provides a substantial improvement in the description of the data compared to tp approximations. These results demonstrate the importance of accurate treatments of the off-energy-shell properties of effective interactions as well as the mixed density in calculating nonrelativistic optical potentials for intermediate energy nucleon scattering. Exploratory calculations at 500 MeV together with those at lower energies suggest the need for an improved description of the nucleon-nucleon interaction at higher energies.