Jülich-Bonn-Washington Model for Pion Electroproduction Multipoles

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 GeV < W < 1.6 GeV and Q 2 below 6 GeV 2 are included. The model is an extension of the latest Jülich-Bonn solution incorporating constraints from pion-induced and photoproduction data. Performing large scale fits (∼ 10 5 data) we find a set of solutions with χ 2 dof = 1.69 − 1.81 which allows us to assess the systematic uncertainty of the approach.

New graphical criterion for the selection of complete sets of polarization observables and its application to single-meson photoproduction as well as electroproduction

“…Then, after fitting the data, the resulting amplitude is analytically continued into the complex energy-plane in order to search for the resonance-poles. Well-known examples for such approaches are the SAIDanalysis [34][35][36][37][38], the Bonn-Gatchina model [39][40][41][42], the Jülich-Bonn model [43][44][45][46][47] and the MAID-analysis [48][49][50][51], among others.…”