Nucleon resonances in gamma p -> omega p reaction

The most recent high-precision data on spin observables Sigma, T, P', E, F, and H reported by the CLAS Collaboration together with the previous data on differential cross sections and spin-density-matrix elements reported by the CLAS, A2, GRAAL, SAPHIR, and CBELSA/TAPS Collaborations for the reaction gamma p -> omega p are analyzed within an effective Lagrangian approach. The reaction amplitude is constructed by considering the t-channel pi and eta exchanges, the s-channel nucleon and nucleon resonances exchanges, the u-channel nucleon exchange, and the generalized contact current. The latter accounts effectively for the interaction current and ensures that the full photoproduction amplitude is gauge invariant. It is shown that all the available CLAS data can be satisfactorily described by considering the N(1520)3/2(-), N(1700)3/2(-), N(1720)3/2(+), N(1860)5/2(+), N(1875)3/2(-), N(1895)1/2(-), and N(2060)5/2(-) resonances in the s-channel. The parameters of these resonances are extracted and compared with those quoted by PDG.