Features of $omega$ photoproduction off nucleon target at forward angles: dominance of $pi$ exchange with Regge cuts and scaling of differential cross-sections

We investigate the photoproduction of omega off a nucleon target gamma N -> omega N by using a Reggeized model where pi(135) + sigma(500) + f(1)(1285) + f(2)(1270) + pomeron exchanges are included in the t-channel for the reaction at forward angles. The reaction mechanism at low energy is featured by the dominance of the pi exchange with the absorptive cuts introduced to modulate the pion contribution to both gamma p -> omega p and gamma n -> omega n reactions. The necessity of exchange is illustrated in the analysis of the cross-section from natural parity exchanges. Cross-sections for the differential, total, and spin density matrix with parity and beam polarization asymmetries are reproduced and compared with existing data on gamma p -> omega p. Scaled differential cross-sections of Jefferson Lab data on gamma p -> omega p are investigated at the production angle theta = 90 degrees with the nonlinear trajectories for a saturation. Differential and total cross-sections for the gamma n -> omega n reaction are analyzed to compare with recent experimental data at the CBELSA/TAPS Collaboration. An application of the gamma p -> omega Delta(+) reaction is presented to demonstrate the significance of the pi exchange in the total and differential cross-sections.