The role of low mass nucleon resonances in near threshold w meson photoproduction

We investigate the role of the nucleon resonances with masses M-N* <= 1720 MeV in w meson photoproduction at low energy with E-gamma <= 1.25 GeV. The amplitude is calculated within effective Lagrangian approach, which includes, at the tree level, leading t-channel pseudoscalar meson exchange, nucleon Born terms and nucleon resonance excitations. For the later part we use an effective Lagrangians motivated by previous studies of pi and eta photoproduction. The contributions from the nucleon resonances are found to be significant relative to the all other channels in changing the differential cross sections in a wide interval of t In particular, we suggest that a crucial test of our predictions can be made by measuring single and double spin asymmetries.