Polarization of Nucleons Scattered by Nuclei

Abstract

The polarization of nucleons scattered by nuclei yields useful information regarding the compound state of the nucleon-nucleus system. In particular it has been shown by Critchfield and Dodder [1] in the case of p-He⁴ scattering that the resonance observed in the region 3 to 10 Mev is connected with a nucleon-nucleus interaction in which the 2p $\frac{3}{2}$ state has a larger phase shift than that of 2p ½. The direction as well as the magnitude of this spin-orbit interaction fits in with the expectations from the Mayer-Jensen, Suess, Haxel shell theory of nuclear structure. Similarly it has been found by Fermi [2] that high energy nucleon-nucleus scattering indicates agreement with the shell theory¹. Since these results are concerned with energy states lying much higher than those dealt with in most of the analysis of empirical material on shell structure they may be considered as significant indicators of the approximate validity of the phenomenologic aspects of the spin-orbit potential hypothesis made in shell theory. Within the last few years there appeared tentative indications of consistency between the relatively large nucleon-nucleus polarizations and the phase shifts suggested by nucleon-nucleon scattering. The significance of these developments appears to justify a summary in this collection of the theory used in deriving the polarization from experiment and in calculating the polarization from the phase shifts or else from parameters of the optical model.