Quasifree knockout of charged particles from 4He with 100 MeV protons

Exclusive measurements have been made of 4He(p,2p), (p,pd), (p,pt), and (p,ph) at 100 MeV. The primary protons were measured at two angles, 45 degree and 60 degree, in coincidence with secondary protons, deuterons, tritons, or helions covering a wide range of angles on the opposite side of the beam, from -15 degree to -90 degree in plane, and from 0 degree to 30 degree out of plane. The satisfactory agreement in shape between the measured energy-sharing distributions and results of distorted-wave impulse approximation calculations suggests that this formalism is adequate for modeling the quasifree knockout reactions induced by 100 MeV protons on 4He. It is found that (70±10)% of the inclusive continuum yields in 4He(p,p') is attributable to quasifree scattering, with ∼30% arising from multiple scattering. At low energies of the scattered proton, the knockout of nucleons constitutes over 90% of the quasifree component, whereas at high energies the knockout of deuterons, tritons, and helions dominates the yield. Consequently the cluster knockout contributions fill in the yield at higher energies in the inclusive spectra, and quasifree peaks are not discernible