$\eta$ MAID-2015: update with new data and new resonances

Abstract

Recent data for $\eta$ and $\eta\prime$ photoproduction on protons obtained by the A2 Collaboration at MAMI are presented. The total cross section for $\eta$ photoproduction demonstrates a cusp at the energy corresponding to the $\eta\prime$ threshold. The new data and existing data from GRAAL, CBELSA/TAPS, and CLAS collaborations have been analyzed by an expansion in terms of associated Legendre polynomials. %A Legendre decomposition shows the sensitivity to small partial-wave contributions. The isobar model $\eta$MAID updated with $\eta \prime$ channel and new resonances have been used to fit the new data. The new solution $\eta$MAID-2015 reasonably good describes the data in the photon beam energy region up to 3.7 GeV.