Unified theory of NN →πd, πd →πd and NN →NN  reactions

Using a set of equations that couple the N-N to the π-d channel and satisfy two- and three-body unitarity, we have studied in detail the reaction pp→π⁺d, and πd→πd and NN→NN scattering. We find that the equations give a very good description of the differential cross sections and some of the polarization data for both pp→π⁺d and πd→πd over the energy region 47<T_π<256 MeV. We observe that for pp→π⁺d, higher partial waves (l_πd >2) contribute significantly to both the differential cross section and analyzing power. Including the P₁₁ π-N interaction and thus true absorption in π-d elastic scattering, we find a cancellation between the pole and nonpole parts of the P₁₁ amplitude. A major part of the effect of true absorption is in J^π=0⁺, which contributes little to the absorption cross section. The sensitivity of the results to the D state of the deuteron and the choice of the πNN form factor is investigated. For N-N scattering the agreement with the experimental phase shifts is better in the singlet than triplet channels. This is due to the absence of vector meson exchange in the calculation. The ¹D₂ phase shift exhibits resonance behavior in the absence of a pole in the amplitude.