Spin and quasifree proton-proton scattering onHe3andHe4

Theoretical expressions for the differential cross section of symmetric, coplanar ($p,2p$) quasifree scattering on ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ are derived in the plane-wave impulse approximation with full account given to the spin effects of the nucleon-nucleon interaction and the nuclear bound states. The phenomenological $M_{12}$ matrix is utilized as are correlated functions and Eckart parametrizations of the distribution functions for the light nuclei. Shape fits to experimental data for the Eckart parametrizations are found to be extremely good although theory overpredicts the magnitudes of the cross sections. It is shown that an intuitive extension of the attenuation model of Rogers and Saylor is able to remove this latter discrepancy in ${}_{}{}^3{}_{}{}^{}\mathrm{He}\mathrm{}(p,2p)\mathrm{}{}_{}{}^2{}_{}{}^{}\mathrm{H}$. We also indicate the possible usefulness of our matrix elements in polarization studies.