Pion Photoproduction at Backward Angles Near the Second Nucleon-Pion Resonance

Abstract

An experiment is described in which photons with energies of 500 to 820 Mev strike a liquid hydrogen target. The center-of-mass differential cross sections for pi /sup +/ photoproduction from the hydrogen are measured at laboratory angles of 135 and 180 deg for various photon energies. Differences between the photoproduction resonance peaks and pi /sup -/ -p total cross sections are discussed, and conclusions are suggested as to the existence of a T = 1/2 resonant state in the pion-nucleon interaction about 320 Mev center-ofmass above the J = 3/2, T = 3/2 resonance. (T.F.H.)