Analysis of resonance multipoles from polarization observables in η photoproduction -: art. no. 035210

A combined analysis of new eta photoproduction data for total and differential cross sections, target asymmetry, and photon asymmetry is presented. Using a few reasonable assumptions we perform the first model-independent analysis of the E0+, E2-, and M2- era photoproduction multipoles. Making use of the well-known A(3/2) helicity amplitude of the D-13(1520) state, we extract its branching ratio to the eta N channel, Gamma(eta N)/Gamma = (0.08 +/- 0.01)%. At higher energies, we show that the photon asymmetry is extremely sensitive to small multipoles that are excited by photons in the helicity 3/2 state. The new GRAAL photon asymmetry data at higher energy show a clear signal of the F-15(1680) excitation which permits extracting an F-15(1680) --> eta N branching ratio of (0.15(-0.10)(+0.35))%. [S0556-2813(99)01809-9].