''Soft-pion'' production in the reaction NN→NNπ

We examine the reaction NN→NNπ for ''soft-pion'' kinematics (p/sub π/=0 in the center of mass). An earlier calculation based on the Adler-Dothan theorem severely underestimated the p/sub π/=0 cross section for pp→npπ+ at 740 MeV. We attempt to understand this discrepancy in the context of a relativistic, unitary, three-body isobar model. The postemission Δ-pole contributions are shown to be very important, even for these ''soft-pion'' kinematics. Relatively high partial waves in the NN→NΔ isobar amplitude are significant. However, after summing all the postemission and preemission diagrams, the discrepancy with experiment is only partially removed