Photoproduction of Neutral Pions at Energies 600 to 800 Mev

The photoproduction of neutral π mesons from hydrogen has been studied at the California Institute of Technology Synchrotron Laboratory by detecting recoil protons from a liquid hydrogen target irradiated by the synchrotron bremsstrahlung beam. The recoil protons were detected by a five-counter telescope. Data were taken at proton laboratory angles of 19^∘{}, 30^∘{}, 40^∘{}, 50^∘{}, and 60^∘{} at proton energies corresponding to photon energies of 600, 700, and 800 Mev. Angular distribution data are produced at these three energies and fitted with functions of the form: A+Bcosθ_π^'+Ccos²θ_π^'. These functions are qualitatively like those at lower energies; B is small and -A/C is roughly 1.25. The total cross section is found to have a minimum at about 600 Mev, being slightly larger at 700 and 800 Mev.