Baryon Transition Form Factors from Dynamical Coupled-Channel Analyses

TL;DR

This paper presents a comprehensive analysis of electromagnetic transition form factors from the nucleon ground state to various excited states using a coupled-channel approach, providing new insights into resonance behaviors up to 1.8 GeV.

Contribution

It introduces a detailed coupled-channel analysis of transition form factors for multiple nucleon resonances, including uncertainties, based on extensive electroproduction data.

Findings

Qualitative agreement with previous results for N(1440) and Δ(1232)

First resonance pole definitions for other states

Uncertainty estimates for form factors

Abstract

In this talk, the electromagnetic transition form factors from the nucleon ground state to twelve $N^*$ and $\Delta$ states are exhibited and discussed. Those results are extracted through a comprehensive coupled-channel approach -- the Juelich-Bonn-Washington model, with the center-of-mass energy ranging from $1.13$ GeV to $1.8$ GeV, and the photon virtuality up to $8$ GeV$^2$. The extraction is based on $10^5$ electroproduction data points of $\pi N$, $\eta N$, and $K\Lambda$ channels, with additionally about $5\times 10^4$ data points in the hadronic sector as well as photoproductions as boundary conditions. The form factors are defined from the residues at the corresponding resonance poles in the multipole amplitudes. Uncertainties are also estimated by the exploration of the parameter space. The qualitative behavior of the transition form factors of $N(1440)$ and $\Delta(1232)$ here are in agreement with the previous studies, while for the other states, there has not been literature results that are also defined at the resonance poles.