Quasielastic proton-nucleus scattering in a relativistic plane-wave impulse approximation

Proton-nucleus quasielastic scattering cross sections and spin observables are calculated in a relativistic plane-wave impulse approximation for nuclei from C12 to Pb208 at energies of 300 to 800 MeV. Relativistic effects are incorporated by using Dirac spinors with enhanced lower components characterized by an effective mass from 0.8 to 0.9M. The analyzing power is found to decrease significantly from free NN values when relativistic spinors are used. This reduction is in good agreement with data. Little change in polarization transfer coefficients Dij is found at 500 MeV. However, predictions of enhanced Dss and Dll are made at lower energies. Calculations are also presented for (p,n) quasifree charge exchange reactions. Here the analyzing power is almost unchanged but large changes in cross section and polarization transfer coefficients are possible. These changes depend on how pion contributions to the NN amplitudes are treated. Suggestions for future theoretical and experimental work are made.