Coupled-channel analysis of pion- and eta-electroproduction with the J\"ulich-Bonn-Washington model

TL;DR

This paper presents a joint analysis of pion and eta electroproduction data up to 1.6 GeV using a coupled-channel model, providing insights into the amplitudes' determination and the model's effectiveness.

Contribution

It introduces the first combined analysis of pion and eta electroproduction data within a dynamical coupled-channel framework based on the Jülich-Bonn-Washington model.

Findings

Some amplitudes are well determined near threshold.

Other amplitudes need extended energy range fits.

Comparison with single-channel fits highlights strengths and limitations.

Abstract

Pion and eta electroproduction data are jointly analyzed for the first time, up to a center-of-mass energy of 1.6 GeV. The framework is a dynamical coupled-channel model, based on the recent J\"ulich-Bonn-Washington analysis of pion electroproduction data for the same energy range. Comparisons are made to a number of single-channel eta electroproduction fits. By comparing multipoles of comparable fit quality, we find some of these amplitudes are well determined over the near-threshold region, while others will require fits over an extended energy range.