Quark model study of the eta photo-production: Evidence for a new S-11 resonance?

An extensive and systematic study of the recent eta photo-production data u p to 1.2 GeV is presented within a chiral constituent quark model. A model embodying all known nucleonic resonances shows clear need for a yet undisco vered third S-11 resonance in the second resonance region, for which we det ermine the mass (1.729 GeV) and the total width (183 MeV). Furthermore, we extract the configuration mixing angles, an important property of the quark -quark interaction in the quark model, for the resonances S-11(1535) and S- 11(1650), as well as for the resonances D-13(1520) and D-13(1700). Our resu lts agree well with the quark model predictions. In addition, the partial e taN decay, widths and/or the photo-excitation helicity amplitudes for the n ucleonic resonances S-11(1535), S-11(1650), P-11(1710), P-13(1720), D-13(15 20), D-13(1700), D-15(1675), and F-15(1680) are also obtained in this appro ach.