Measurements of NN → dπ very near threshold

Abstract We have measured cross sections for the reaction np→d π 0 at beam energies very near the pion-production threshold. The yield near threshold is 23% lower than the previously accepted value based on π + d→pp data. P-wave pion production was observed at energies as low as 1.5 MeV (c.m.) above threshold. There was no evidence of narrow πNN resonances in the energy range surveyed - 275 to 291 MeV, corresponding to pion c.m. momenta between 2 and 43 MeV/ c .