Polarization in the (p,π) reaction

Recent experimental results indicate a dominance of fundamental NN→NNπ processes in near‐threshold nuclear pion production. Such two‐nucleon processes are revealed in part by distinct polarization effects characterizing both weak (ground state) and strong, highly selective, maximal J coupling transitions for the (p,π−) reaction. For (p,π+), where several NN processes can contribute coherently, analyzing power data suggest a means of distinguishing the contributions from different fundamental NN→NNπ isospin channels.