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Angular distributions of the differential cross section for the reaction γ +p→ π 0 +p have been measured at the Bonn 2.5 GeV Synchrotron at c.m. angles between 0° and 65° in the energy range from 1.3 GeV to 2.2 GeV. The π 0 mesons were detected by their two decay photons. The data are compared with data of other laboratories and the Metcalf-Walker analysis.

Angular distributions of the target symmetry for the reaction γ + p → π0 + p have been measured at the Bonn 2.5 GeV Electron Synchrotron at pion c.m. angles between 13° and 63° and photon energies of 1.0 and 1.1 GeV. The π0 mesons were detected by their two decay photons with total absorption lead-glass Cerenkov counters. Butanol was used as target material in a continuous flow 3He cryostat operating at 0.5 K and 25 kG. The π0 counting rate from free protons in the butanol target was derived from the measurements of the differential cross section on hydrogen. The data are compared with data of other laboratories and the results of two recent partial-wave analyses.

Four angular distributions of the differential cross section of the reaction γ + p → π 0 + p have been measured at the Bonn 2.5 GeV Synchrotron at pion c.m. angles between 3° and 63° in the photon energy range from 0.9 GeV to 1.2 GeV. The π 0 mesons were detected by their two decay photons. The data are compared with data of other laboratories and predictions of two recent partial-wave analyses.