The role of momentum dependent dressing functions and vector meson dominance in hadronic light-by-light contributions to the muon g-2

TL;DR

This paper refines the calculation of the quark-loop contribution to the muon's anomalous magnetic moment by analyzing the impact of momentum-dependent dressing functions and vector meson dominance, revealing potential overestimations in simpler models.

Contribution

It provides a detailed comparison of the transverse quark-photon vertex structures using refined methods and highlights the importance of momentum-dependent dressing functions in accurate calculations.

Findings

Transverse quark-photon vertex structures suppress the muon g-2 contribution.

Simple models may overestimate the suppression effect.

Momentum dependence is crucial for precise theoretical predictions.

Abstract

We present a refined calculation of the quark-loop contribution to hadronic light-by-light scatter- ing that focuses upon the impact of the transverse components of the quark-photon vertex. These structures are compared and contrasted with those found within the extended NJL-models. We discuss similarities and differences between the two approaches and further clarify the important role of momentum dependent dressing functions. As expected we find that the transverse structures of the quark-photon vertex lead to a suppression of the quark-loop contribution to the anomalous magnetic moment of the muon. However, we find evidence that this suppression is overestimated within models with simple approximations for the quark-photon interaction.