Exchange effects and large angle proton scattering on light nuclei at intermediate energies: p+3He scattering.

Abstract

A model developed previously to treat p+ /sup 4/He scattering at intermediate energies is applied to the case of p+ /sup 3/He scattering. The scattering amplitude is written as a sum of direct and exchange terms. The direct-plus-knockout exchange terms are approximated by a phenomenological optical potential scattering amplitude. The heavy particle stripping term, representing the exchange of a neutron-proton cluster between projectile and target, is calculated using a modified distorted-wave Born approximation approach. The point-nucleon wave function for the /sup 3/He target is determined from a fit to the charge form factor, after subtraction of recently calculated meson exchange current contributions. The back-angle rise in the differential cross section in the energy range 150--600 MeV is reproduced qualitatively when the heavy particle stripping term is included. In addition, a slight improvement in the large angle analyzing power is obtained at 300 and 515 MeV.