Progress in the calculation of nucleon transition form factors

TL;DR

This paper reviews the Dyson-Schwinger and Faddeev-equation methods for calculating nucleon transition form factors, comparing different models and discussing their timelike structures and advantages over helicity amplitudes.

Contribution

It introduces a quark-diquark approach for nucleon resonances and compares it with the three-body approach, providing new insights into their calculations.

Findings

Quark-diquark model effectively describes low-lying nucleon resonances.

Timelike transition form factors reveal detailed internal structure.

Form factors offer advantages over helicity amplitudes in analysis.

Abstract

We give a brief account of the Dyson-Schwinger and Faddeev-equation approach and its application to nucleon resonances and their transition form factors. We compare the three-body with the quark-diquark approach and present a quark-diquark calculation for the low-lying nucleon resonances including scalar, axialvector, pseudoscalar and vector diquarks. We also discuss the timelike structure of transition form factors and highlight the advantages of form factors over helicity amplitudes.