MULTIPOLE E1+(3/2) OF PHOTOPION PRODUCTION ON NUCLEONS AND ITS DOUBLE ZERO AT THE RESONANCE DELTA-(1232)

The multipole E1+(3/2) of photoproduction of pions on nucleons in the region of the first resonance has been calculated with the use of relativistic dispersion relations supplemented with the values of pion-nucleon scattering phase-shifts at moderate energies and with summary information on the dynamics in the region of higher energies. This approach, which has previously been applied successfully to the magnetic dipole amplitude M1+(3/2) of photo- and electroproduction of pion on nucleons, is shown to work remarkably well in the case of E1+ (3/2) also.