Comparison of the ReactionHe4(p, 2p)H3at Intermediate Energies with the Distorted-Wave Impulse Approximation

The ${}_{}{}^4{}_{}{}^{}\mathrm{He}(p, 2p){}_{}{}^3{}_{}{}^{}\mathrm{H}$ reaction has been measured at 250, 350, and 500 MeV using symmetric geometries. The energy dependence of the cross section at zero recoil momentum and angular distributions are presented. The data are compared to distorted-wave impulse-approximation (DWIA) calculations. Unlike at lower energies, the zero-recoilmomentum data are well described by the DWIA at these energies. For the angular distributions, the DWIA increasingly underestimates the data as the recoil momentum is increased.