Interference phenomena in the JP = 1/2− wave in η photoproduction

The recent precise experimental results for the photoproduction of η-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina coupled-channel model. The main result is that the narrow structure observed in the excitation function of γη → nη can be reproduced fully with a particular interference pattern in the J P = 1/2− partial wave. Introduction of the narrow resonance N(1685) with the properties reported in earlier publications deteriorates the quality of the fit.