Positive-Pion Photoproduction at 180 Degrees Near the Second Nucleon-Pion Resonance

摘要

In a previous experiment the cross section for the photoproduction of pions in hydrogen near the second pion nucleon resonance was measured at 135 degrees and 180 degrees in the CMS. At 180 degrees the measurements did show a very sharp peak at a gamma ray energy of 700 MeV. The experiment has now been repeated only at 180 degrees, with improved energy resolution. The new results, in agreement with the old ones, show the same sharp energy dependence at about the same value of the primary energy. (Author)