Fixed poles of photonic amplitudes involving compositeness

The existence and significance of the right-signature J = 0 fixed pole in vector scattering such as photoproduction and Compton scattering off protons and pions is investigated in the context of gauge invariant models involving compositeness which have been developed in a previous note. It is shown that the existence of such a fixed pole depends on the elementarity of the photon and not on the compositeness of the pion or proton target or on the assumption that the charged constituent of the target have no s true ture . Assuming the p-meson lies on a Regge trajectory, we show that within the context of these models a J = 0 fixed pole does not arise in p-meson photoproduction. (Submitted to Phys. Rev. ) *Work supported in part by the U. S. Atomic Energy Commission. T Max Kade Foundation Fellow. On leave from University of Trier-Kaiserslautern, Kaiserslautern, Germany.