Resonance contributions to η photoproduction on protons found using dispersion relations and an isobar model -: art. no. 065204

Using dispersion relations good description of existing data on eta photoproduction on protons in the resonance energy region is obtained, and the contributions of the resonances D-13(1520), S-11(1650), D-15(1675), F-15(1680), D-13(1700), P-11(1710), P-13(1720) to gammap-->etap are found. In order to estimate model dependence of the obtained resonance characteristics, an isobar model is used for the analysis of the same data. We conclude that the results for the contributions of the resonances D-13(1520), S-11(1535), S-11(1650), F-15(1680) to corresponding multipole amplitudes are stable. With this the results for D-13(1520) and F-15(1680), combined with their Particle Data Group (PDG) photoexcitation helicity amplitudes, allow to find the branching ratios Br[D-13(1520)-->etaN]=(0.05+/-0.02)%, Br[F-15(1680)-->etaN]=(0.16+/-0.04)% which have significantly better accuracy than the PDG data. The total Breit-Wigner width of the S-11(1535) is model dependent. We have obtained Gamma[S-11(1520)]=142 MeV and 195 MeV using dispersion relations and the isobar model, respectively. The results for the D-15(1675), P-11(1710), P-13(1720) obtained in two approaches are close to each other. The results for the D-13(1700) are model dependent.