Nuclear spin response to inelastic proton scattering: Finite geometry and absorption effects

Recent experiments have clearly demonstrated the ability of inelastic proton scattering to act as a precise probe of the nuclear spin response. Previous calculations based on infinite or semi-infinite matter models differ markedly from experiment in their prediction of longitudinal to transverse response function ratios. The present work indicates that finite geometry and absorption effects are crucial in bringing predictions closer to experiment. The effect of including isobar excitations is also investigated and assessed critically. (orig.)