Spin observables in proton-4He elastic scattering at 800 MeV

The present calculation, devoted to proton-4He elastic scattering at 800 MeV, is the first to achieve good agreement with experimental data for polarization P and spin rotation parameters Q, S, starting from an accurate knowledge of the basic nucleon-nucleon amplitudes. We have studied the influence of Δ propagation in the intermediate steps of multiple scattering and the phase variation of the nucleon-nucleon amplitudes with momentum transfer. Both effects play an important role. General formulae are derived to test the NΔ elastic scattering within the nucleus. (author)