Non-relativistic effective interactions and polarization phenomena

Effective interactions based on free nucleon-nucleon t-matrices and on G-matrices calculated in symmetric nuclear matter are considered within a single scattering description of nucleon-nucleus scattering. Some of the ambiguities encountered in constructing G-matrix interactions are outlined and some of the largest density-dependent modifications to the free t-matrix are illustrated. The influence of medium modifications on the interpretation of polarization phenomena is studied by applying both t- and G-matrix interactions to the calculation of a variety of recently measured nucleon-nucleus spin observables. Qualitative relationships between free nucleon-nucleon amplitudes and nucleon-nucleus spin observables are demonstrated. (author)