Elastic Photoproduction of π0 Mesons From Deuterium in the Energy Range From 500 MeV to 700 MeV

The reaction, γ+ d → d +π 0 , has been used to measure the isotopic vector part of the photopion production amplitude from nucleons around the second resonance. The differential cross sections have been measured at 57.6° (lab) for E γ =500∼700 MeV. The momentum of recoil deuterons was analyzed with a magnet and their flight time was measured with a time-to-pulse height converter, to discriminate deuterons from protons and pions. The measured cross sections were analyzed in terms of the π– N phase shifts basing on the impulse approximation. The s 3 –, s 1 –, p 33 –, p 11 – and d 13 – phase shifts are included in this analysis. The measured cross sections are in fairly good agreement with the calculation. However, the cross sections calculated in the absence of the d 13 –wave are smaller by about 40% than the measured ones. The results of analysis are consistent with the assumption that the d 13 –wave amplitude of photoproduction from free nucleons is an isotopic vector.