Structure of the phi 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 me chanisms. The SU(3) symmetry and the phi decay widths are exploited to dete rmine the parameters that are needed to predict the amplitudes due to pseud oscalar mesons (pi(0), eta) exchange, scalar mesons (sigma a(0),f(0)) excha nge, 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 i nvestigate the role of a second Pomeron with alpha(0) < 0, as inspired by t he glueball (J(pi) = 0(+), M-b(2) similar to 3 GeV2) predicted by the latti ce QCD calculation and dual Ginsburg-Landau model. It is found that the exi sting limited data at low energies near threshold can accommodate either th e second Pomeron or the scalar mesons exchange. The differences between the se two competing mechanisms are shown to have profound effects on various d ensity matrices which can be used to calculate the cross sections as well a s various single and double polarization observables. We predict a definite isotopic effect: polarization observables of phi photoproduction on the pr oton and neutron targets can have differences of a factor 2 and more. [S055 6-2813(99)04908-0].