Spin observables in pseudoscalar meson photoproduction

The energy evolution and angular structure of low energy pseudoscalar meson photoproduction spin observables are analyzed. Nodal trajectories, e.g. plots of angular nodes versus photon energy, and/or polynomial expansions are shown to be useful ways to identify effects due to underlying dynamics. Guidelines for the anticipated, or 'normal,' behavior of eta photoproduction spin observables are generated based on several bold assumptions: (1) resonance dominance; (2) a feasible truncation of multipoles and (3) assuming negligible background effects. Observables that are particularly sensitive to missing nucleonic resonances predicted by quark-based approaches, are singled out.