Structure of the φ photoproduction amplitude at a few GeV -: art. no. 035205

The structure of the phi photoproduction amplitude in the root s similar to 2-5 GeV region is analyzed based on Pomeron-exchange and meson-exchange mechanisms. The SU(3) symmetry and the phi decay widths are exploited to determine the parameters that are needed to predict the amplitudes due to pseudoscalar mesons (pi(0), eta) exchange, scalar mesons (sigma a(0),f(0)) exchange, and the phi radiation from the nucleon. In addition to the universally accepted Pomeron exchange with an intercept alpha(0) similar to 1.08, we investigate the role of a second Pomeron with alpha(0) < 0, as inspired by the glueball (J(pi) = 0(+), M-b(2) similar to 3 GeV2) predicted by the lattice QCD calculation and dual Ginsburg-Landau model. It is found that the existing limited data at low energies near threshold can accommodate either the second Pomeron or the scalar mesons exchange. The differences between these two competing mechanisms are shown to have profound effects on various density matrices which can be used to calculate the cross sections as well as various single and double polarization observables. We predict a definite isotopic effect: polarization observables of phi photoproduction on the proton and neutron targets can have differences of a factor 2 and more. [S0556-2813(99)04908-0].