Polarization phenomena in the reaction NN to NNpi near threshold

Abstract

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

10 pages, 4 figures