THRESHOLD NEUTRAL PION PHOTOPRODUCTION ON THE PROTON AND THE CLOUDY BAG MODEL

The energy dependence of the electric dipole amplitude, the total and differential cross-sections of the photoproduction of neutral pions off protons near threshold is given. The amplitude of process is a sum of the LET prediction and the additional term connected with the chiral symmetry breaking interaction. The simple K-matrix calculations are used to estimate the change in the electric dipole amplitude and the total and differential cross-sections between π0p and π+n thresholds.