PseudoscalarπNcoupling and relativistic proton-nucleus scattering

Relativistic p${\mathrm{-}}^{40}$Ca elastic scattering observables are calculated using relativistic NN amplitudes obtained from the solution of a two-body relativistic equation. Results at 200 MeV are presented for three sets of NN amplitudes, two with pure pseudovector coupling for the pion and one with a 25% admixture of pseudoscalar coupling. Differences between the predictions of these three models provide a measure of the uncertainty in constructing Dirac optical potentials from NN amplitudes.