Final-state interactions and quasi-free scattering in the 2H(α, pα)n reaction

Abstract

The 2H(α, pα)n reaction has been studied in a kinematically complete experiment at several angles and energies suitable for observing proton-α quasi-free scattering (QFS) and proton-neutron final-state interaction (FSI). The data have been analyzed in terms of various quasi two-body models, taking into account the strong contributions from p-α and n-α interactions in the ground states of 5Li and 5He which are present in most of the spectra. A modified impulse approximation was found to describe reasonably well the spectra dominated by p-α QFS and FSI. A characteristic increase of yield has been observed in the region of low relative p-n energy which can only be explained by the admission of at least 1% of isospin forbidden proton-neutron FSI in the spin-singlet state.