Polarization in Scattering by Complex Nuclei

Abstract

Polarization effects in the elastic scattering of high-energy nucleons by complex nuclei are studied in terms of the impulse approximation. The principal aim is to reconcile the large polarization produced by complex nuclei with the smaller effects found in nucleon-nucleon scattering. It is shown that these results are not inconsistent and can indeed be understood in terms of simple physical arguments. While, in general, our knowledge of nuclear structure is not adequate for explicit calculation of these effects even in the impulse approximation, it can be shown that for a particular class of nuclei (the deuteron and the alpha-particle nuclei) the polarization is independent of the nuclear wave function. Calculations for these nuclei have been carried out in detail, using existing nucleon-nucleon phase shifts. The resulting polarization effects are found to be large, in rough agreement with experiment, although their angular dependence is not satisfactory. It is proposed that a study of polarization in elastic scattering by deuterium and helium be used as a tool for investigation of the nucleon-nucleon interaction.