NEAR-THRESHOLD PROTON-INDUCED NEUTRAL PION-PRODUCTION FROM C-12

The total cross section and angular distributions for the differential cross section and the analyzing power of the exclusive two-body pion production reaction C-12(p -->, pi0)N-13g.s. have been measured at 147 MeV, very near the threshold energy of 145 MeV. Both the large forwar d-backward asymmetry in the angular distribution of the differential c ross section and the large values observed for the analyzing powers in dicate strong interference between the amplitude for s-wave pion emiss ion and the amplitudes for p-wave pion emission. A phase-shift analysi s performed on these new data yields significant p-wave strength at th is low energy. The measurements for pi0 production from carbon are in agreement with results extracted from existing data for pi+ production from carbon, after corrections for isospin invariance and Coulomb eff ects. The reduced s-wave strength is found to have a simple power law dependence on the total number of nucleons in the final bound state.