Eta and etaprime photoproduction on the nucleon with the isobar model EtaMAID2018

2018 
The isobar model EtaMAID has been updated with new and high precision data for $\eta$ and $\eta^{\prime}$ photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The background is described in a recently developed Regge cut model, and for the resonance part the whole list of nucleon resonances has been investigated with 21 $N^{\ast}$ states contributing to $\eta$ photoproduction and 12 $N^{\ast}$ states contributing to $ \eta^\prime$ photoproduction. A new approach is discussed to avoid double counting in the overlap region of Regge and resonances. A comparison is done among four newly updated partial waves analyses for observables and partial waves. Finally, the possibility of a narrow resonance near $W = 1900$ MeV is discussed, that would be able to explain unexpected energy and angular dependence of observables in $ p(\gamma,\eta^{\prime})p$ near $\eta^{\prime}$ threshold.
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