Unified description of hadron-photon and hadron-meson scattering in the Dyson-Schwinger approach

TL;DR

This paper develops a unified nonperturbative framework within QCD to describe hadron interactions with photons and mesons, enabling consistent analysis of various scattering processes.

Contribution

It introduces a general method to derive hadron couplings to external currents using Dyson-Schwinger equations, unifying photon and meson interactions in a single approach.

Findings

Derived expressions for hadron coupling to external currents.

Analyzed four-point functions for various scattering processes.

Potential to describe experimental phenomena like Compton scattering and meson production.

Abstract

We derive the expression for the nonperturbative coupling of a hadron to two external currents from its underlying structure in QCD. Microscopically, the action of each current is resolved to a coupling with dressed quarks. The Lorentz structure of the currents is arbitrary and thereby allows to describe the hadron's interaction with photons as well as mesons in the same framework. We analyze the ingredients of the resulting four-point functions and explore their potential to describe a variety of processes relevant in experiments. Possible applications include Compton scattering, the study of two-photon effects in hadron form factors, pion photo- and electroproduction on a nucleon, nucleon-pion or pion-pion scattering.