Polarization phenomena in the reaction NN to NNpi near threshold

Abstract

First calculations for spin-dependent observables of the reactions $pp \to ppπ^0$, $pp \to pnπ^+$ and $pp \to dπ^+$ near threshold are presented, employing the Jülich model for pion production. The influence of resonant (via the excitation of the $Δ(1232)$) and non-resonant p-wave pion production mechanisms on these observables is examined. For the reactions $pp \to pnπ^+$ and $pp \to dπ^+$ nice agreement of our predictions with the presently available data on spin correlation coefficents is observed whereas for $pp \to ppπ^0$ the description of the data is less satisfying.