Proton−4He potential derived from phase shifts

Published phase shifts (in R-matrix and effective range parametrized forms) fitted to protons scattering from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, for energies up to 23 MeV, have been inverted to give two alternative energy-dependent local potentials. One is l independent, the other has a substantial Majorana character; there are very strong reasons to prefer the latter as a potential model for proton scattering from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. The analysis has novel features: Energy ‘‘bites’’ are introduced as a tool for exploiting the extension of the iterative-perturbative inversion procedure to ‘‘mixed-case’’ inversion for spin-half projectiles. An analysis of R-matrix parametrized phase shifts for neutrons reveals equal n${\mathrm{-}}^4$He and p${\mathrm{-}}^4$He nuclear potentials.