Relativistic and nonrelativistic impulse approximation descriptions of 300–1000 MeV proton + nucleus elastic scattering

Intermediate energy (300--1000 MeV) proton-nucleus elastic observables, obtained using the relativistic and nonrelativistic impulse approximations, are compared to each other and with p+⁴⁰Ca, ⁴⁸Ca, and ²⁰⁸Pb data. Systematic, energy dependent differences between the model predictions and the data are observed and discussed. The underlying target densities are then adjusted in each model to obtain best fits to the differential cross section and analyzing power data at each energy. The variations in the resulting effective target density parameters show the deficiencies, with respect to the energy dependence, of the relativistic and nonrelativistic impulse approximations. Improvements which may eliminate some of the energy dependence are discussed.