One-pion-exchange analysis of the reaction np → ppπ− from 1.5 to 4.0 GeV/c incident momentum

Abstract The reaction np → pp π − has been studied in the incident-momentum range of 1 to 4 GeV/ c using the DESY 85 cm HBC exposed to a neutron beam. The production of δ(1236) and other baryon states are examined. The reaction is analysed in terms of a one-pion-exchange model using the Durr-Pilkuhn and Benecke-Durr parametrisations. Taking Wolf's set of R parameters, apart from R δ which was set to 1GeV −1 , an adequate description of all features of the data is obtained. σ (np → pp π − ) as function of the neutron momentum is evaluated using the OPE model and the isospin relation between the δ production in np and pp reactions.