Phenomenological Analysis of the Photoproduction of Neutral Vector Mesons and Strange Particles

Abstract

Branching ratios for photoproduction of vector mesons and strange particles are discussed. The one-pion-exchange mechanism cannot explain the observed ratio between $\rho$ and $\omega$ photoproduction cross sections. Various versions of pseudoelastic mechanisms are studied and it is shown that although they correctly predict the large $\rho :\omega$ production ratio, they cannot account for the extremely small preliminary cross section for $\varphi$ production. It is shown that no combination of one-pion exchange and the diffraction mechanism with exact or broken $\mathrm{SU}\left(3\right)\mathrm{}$ can explain the low $\varphi$ production rate. The multiperipheral model may explain the low $\varphi$ production, but predicts the wrong $\rho :\omega$ production ratio. Various possible sources of this discrepancy are studied and experimental tests are discussed which can distinguish between the different proposed theories. A large number of new predictions based on exact or broken $\mathrm{SU}\left(3\right)\mathrm{}$ symmetry are derived and compared with experiment.