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

TL;DR

This paper updates the $ ext{η}$MAID model with new photoproduction data, revealing a cusp at the $ ext{η'}$ threshold and incorporating new resonances to improve data description up to 3.7 GeV.

Contribution

The paper introduces an updated $ ext{η}$MAID model with new data and resonances, enhancing the understanding of $ ext{η}$ and $ ext{η'}$ photoproduction.

Findings

Observed a cusp at the $ ext{η'}$ threshold in cross sections.

Updated $ ext{η}$MAID model fits data well up to 3.7 GeV.

Identified sensitivity to small partial-wave contributions.

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.