Constraining N*(1535) parameters from the eta photoproduction

Current broad uncertainties on the position, total width and eta branching ratio for N* (1535), reported in the 1996 Particle Data Tables, can be narrowed down considerably utilizing the precise Mainz and Bonn data on eta photoproduction. We obtain here a precise determination of the total width from such a study, fixing other parameters. We find the set of N* (1535) parameters, suggested by the Particle Data Group (PDG), to be inconsistent with the experimental results from eta-photoproduction. In particular, values for the photon helicity coupling and/or the eta branching ratio of the resonance, required in order to fit the data, are larger than the PDG values. This result has important consequences for the interpretation of the resonance in the framework of different models, including some exotic possibilities. (C) 1997 Published by Elsevier Science B.V.