SHORT-RANGE EXCHANGE CONTRIBUTIONS TO THE CROSS-SECTION FOR PP-]PP-PI(0) NEAR THRESHOLD

The nuclear S-wave pion production is described by the axial charge density operator of the two-nucleon system, It is shown that the short range axial exchange charge operator implied by the nucleon-nucleon interaction enhances the predicted cross section for the reaction pp--> pppi0 near threshold by factors 3-5. This suffices to explain most of the underprediction obtained with the single-nucleon and S-wave pion rescattering operator. The result implies that the cross section for pp--> pppi0 can provide direct information on the short range components of the nucleon-nucleon interaction.