ar X iv : n uc l - th / 0 10 40 46 v 2 1 6 A pr 2 00 1 HIGHER

We study the role of the nucleon resonances (N *) in ω photoproduction by using the quark model resonance parameters predicted by Capstick and Roberts. The employed γN → N * and N * → ωN amplitudes include the configuration mixing effects due to the residual quark-quark interactions. The contributions from the nucleon resonances are found to be important in the differential cross sections at large scattering angles and various spin observables. In particular, the parity asymmetry and beam-target double asymmetry at forward scattering angles are suggested for a crucial test of our predictions. The dominant contributions are found to be from N 3 2 + (1910), a missing resonance, and N 3 2 − (1960) which is identified as the D 13 (2080) of the Particle Data Group. The nucleon resonances predicted by the constituent quark models have a much richer spectrum than what have been observed in pion-nucleon scattering 1. The origin of this " missing resonance problem " has been ascribed to the possibility that many predicted nucleon resonances (N *) could couple weakly to the πN channel 2. Therefore it would be legitimate to study the nucleon resonances in other reactions and vector meson electromagnetic production is one of them which are under investigation at current experimental facilities such as TJNAF, ELSA-SAPHIR, GRAAL, and LEPS of SPring-8. Theoretically the role of the nucleon resonances was studied by Zhao et al.