Baryons in and beyond the quark-diquark model

TL;DR

This paper investigates nucleon electromagnetic form factors using a Poincare-covariant Faddeev approach with a quark-diquark approximation, highlighting the impact of the quark-photon vertex and comparing results with lattice QCD.

Contribution

It introduces a self-consistent solution for the quark-photon vertex within the Faddeev framework and assesses its effects on nucleon form factors and magnetic moments.

Findings

Transverse parts of the vertex have negligible impact on magnetic moments.

Form factors' quark mass evolution aligns with lattice QCD results.

The quark-diquark model effectively captures nucleon electromagnetic properties.

Abstract

We examine the nucleon's electromagnetic form factors in a Poincare-covariant Faddeev framework. The three-quark core contributions to the form factors are obtained by employing a quark-diquark approximation. We implement the self-consistent solution for the quark-photon vertex from its inhomogeneous Bethe-Salpeter equation. We find that the resulting transverse parts which add to the Ball-Chiu vertex have no significant impact on nucleon magnetic moments. The current-quark mass evolution of the form factors agrees with results from lattice QCD.