Jülich-Bonn-Washington model for pion electroproduction multipoles
Maxim Mai, M. Döring, C. Granados, H. Haberzettl, Ulf-G. Meißner, D. Rönchen, I. I. Strakovsky, R. L. Workman
Abstract
Pion electroproduction off the proton is analyzed in a new framework based on a general parametrization of transition amplitudes, including constraints from gauge invariance and threshold behavior. Data with energies $1.13\phantom{\rule{4pt}{0ex}}\mathrm{GeV}<W<1.6$ GeV and ${Q}^{2}$ below $6\phantom{\rule{4pt}{0ex}}{\mathrm{GeV}}^{2}$ are included. The model is an extension of the latest J\"ulich-Bonn solution incorporating constraints from pion-induced and photoproduction data. Performing large-scale fits ($\ensuremath{\approx}{10}^{5}$ data) we find a set of solutions with ${\ensuremath{\chi}}_{\mathrm{dof}}^{2}=1.69--1.81$ which allows us to assess the systematic uncertainty of the approach.