Vector Meson Photoproduction with an Effective Lagrangian in the Quark Model II: $\omega$ Photoproduction

Abstract

An investigation of $\gamma p\to \omega p$ is presented in a constituent quark model approach. The sparse data in the large $t$ region where the resonances dominate is well described within the model, while the diffractive behavior in the small $t$ region requires an additional t-channel exchange. Taking into account the t-channel ${\pi }^0$ exchange, we find a good overall agreement with the available data with only 3 free parameters. Our study shows that the differential cross section is not sensitive to s-channel resonances, however, the polarization observables are demonstrated to be very sensitive. Thus, measuring polarization observables is the crucial part of the vector meson photoproduction program in the search for "missing" resonances.

Comments: 11 pages, 3 PS figures, submitted to PRC