Phenomenological pp→dπ+ model of A(rvec p,π+)B reactions

A phenomenological pp→dπ+ model of A(rvec p,π+)B reactions is developed that incorporates the full spin dependence of the former reaction. The model makes predictions of analyzing powers and differential cross sections and is applied to an investigation of the (rvec p,π+) reaction on 2H, 3He, 4He, and 12C. The general trends of the predicted observables agree reasonably well with experiment for the helium isotopes. Much greater sensitivity due to effects of absorption and interference between different amplitudes is observed for carbon. Nevertheless, characteristic features of the analyzing powers and differential cross sections for single-particle and two-particle--one-hole states are clearly discerned. Consistent cross section normalization factors between the model and experiment, of the order of unity, are found in nearly all cases over the whole range of nuclei and energies investigated