Dynamical chiral symmetry breaking and the fermion--gauge-boson vertex

TL;DR

This paper introduces a model for the fermion-photon vertex that accurately predicts dynamical chiral symmetry breaking and fermion magnetic moments, independent of gauge choice, aligning well with numerical solutions.

Contribution

A gauge-independent fermion-photon vertex model that reproduces key features of chiral symmetry breaking and fermion magnetic moments.

Findings

Critical coupling for chiral symmetry breaking is gauge-independent.

Model's magnetic moment distribution matches numerical solutions.

Vertex functions depend only on propagator functions, not on angles or gauge parameters.

Abstract

We present a workable model for the fermion-photon vertex, which is expressed solely in terms of functions that appear in the fermion propagator and independent of the angle between the relative momenta, and does not explicitly depend on the covariant-gauge parameter. It nevertheless produces a critical coupling for dynamical chiral symmetry breaking that is practically independent of the covariant-gauge parameter and an anomalous magnetic moment distribution for the dressed fermion that agrees in important respects with realistic numerical solutions of the inhomogeneous vector Bethe-Salpeter equation.