η-production on the proton via electromagnetic and hadronic probes

The reactions π-p →ηn and γ＇p →ηP are investigated within a dynamical coupledJchannels model of meson production reactions in the nucleon resonance region. The meson-baryon channels included are πN, ηN, π△, σN, and pN. The direct wphotoproduction process is studied within a formalism based on a chiral constituent quark model approach, complemented with a one-gluon-exchange mechanism, to take into account the breakdown of the SU（6）0（3） symmetry. In the models search, the following known nucleon resonances are embodied： Sll （1535）, $11（1650）, Pll （1440）, Pl1（1710）, P13（1720）, D13（1520）, D13（1700）, D15（1675）, and F15（1680）. Data for the π-p →ηnreaction from threshold up to a total center-of-mass energy of W ≈ 2 GeV are satisfactorily reproduced. For the photoproduction channel, two additional higher mass known resonances, P13 （1900） and F15 （2000）, are also considered. However, reproducing the data for γ＇p →ηP requires, within our approach, two new nucleon resonances, for which we extract mass and width.