Polarization phenomena in vector meson photoproduction on nucleons near threshold

Abstract

We propose and develop a model for ρ0 and ω photoproduction on nucleons near threshold based on t-, s-, and u-channel amplitudes. In t-channel we consider π- and σ- exchanges and we take the coupling constants (gv,gt) in (s+u) nucleon contributions as free parameters. We fit our model to the available experimental differential cross-section data of γ+p→p+V reactions. We find that different models which are equivalently good for the description of the differential cross-section on proton targets may be differentiated by their predictions of the beam asymmetry on proton and neutron targets and of the differential cross-section on neutron targets.