The shape of the helion spin-orbit potential

Abstract

The detailed shape of the spin-orbit potential needed for helion optical potentials has been determined by measurements with a polarized helion beam. The polarizations produced in the elastic scattering of helions from 26Mg have been measured at 33.4 MeV. The observed polarizations, in conjunction with the elastic differential cross sections, have been analysed using a phenomenological optical models. The geometry of the spin-orbit potential is well determined and is characterized by radius and diffuseness parameters considerably smaller than those of both the real and imaginary potentials. This means that the convention of using the same geometry for the real spin-orbit potentials is no longer acceptable and the use of simple folding models for helion spin-orbit potentials is not justified.