Photoproduction ofπ0Mesons in Hydrogen and Deuterium

Photoproduction of ${\pi }^0$ mesons in hydrogen and deuterium is calculated in the weak coupling theory under several different assumptions regarding the interaction Hamiltonian. All calculations are performed non-relativistically taking into account the anomalous magnetic moments of the nucleons. The contribution of the negative energy states for the nucleons and of the nucleon current are isolated. Calculations are also performed with a phenomenological Hamiltonian which yields a ($2+3{sin\theta }^{\prime }$) angular distribution in the center-of-mass system for the photoproduction of ${\pi }^0$ mesons in hydrogen. In the case of deuterium, the relative importance of elastic and inelastic photoproduction is examined as a function of photon energy, meson angle, and the theoretical results are compared with recent experimental data. Best agreement with experiment is obtained if nucleon current effects are neglected.