On Nucleon-He4Interaction and Nuclear Forces

The nucleon-He/sup 4/ elastic scattering at the incident energies from 0 to 40 Mev is investigated in relation to the nuclear forces. The s-, p-, d-, and f-wave phase shifts are calculated by the nucleon-He/sup 4/ interaction, that is constructed from an approximated Hamada and Johnston nucleon-nucleon potential. The differential cross section and the polarization angular distribution calculated by these phase shifts are compared with the experimentai data. All essential features of the nucleon-He/sup 4/ scattering are explained in the energy region where the inelastic cross section is negligible. Especially the polarization at 40 Mev is fairly reproduced, which is attributed to very small (and negative) values of the d-wave phase shifts. The nucleon-He/sup 4/ interaction depends drastically on the energy and the state, as the result of the presence of large non-local interaction. The nucleon-He/sup 4/ spin-orbit coupling is constructed from the tensor and the spin-orbit part of the nucleon- nucleon forces. It is probable that the strength of the original spin-orbit force is rather weaker at low energies than that known from the high energy proton-proton scattering. (auth)