Extraction of Transition Form Factors for Nucleon Resonances within a Coupled-Channels Model

TL;DR

This paper presents a method using analytic continuation within a coupled-channels model to extract nucleon resonance transition form factors, providing new insights into meson-baryon reactions and resonance properties.

Contribution

It introduces a novel analytic continuation technique to determine resonance pole residues and transition form factors in a dynamical coupled-channel framework.

Findings

Calculated N^* -> pi N, gamma N transition form factors for specific resonances.

Compared results with previous studies, showing consistency and improvements.

Demonstrated the applicability of the method to multiple nucleon resonances.

Abstract

We explain how an analytic continuation we have developed recently is applied to determine the residues of the nucleon resonance poles within a dynamical coupled-channel model of meson-baron reactions. A procedure for evaluating the electromagnetic N-N^* transition form factors at resonance poles is developed. Illustrative results of the obtained N^* -> pi N, gamma N transition form factors for P_{11}, P_{33}, and D_{13} nucleon resonances are presented and compared with previous results.