Axial-vector exchange contribution to the hadronic light-by-light piece of the muon anomalous magnetic moment

TL;DR

This paper calculates the axial-vector exchange contribution to the muon g-2's hadronic light-by-light scattering using resonance chiral theory, highlighting uncertainties and the importance of future experimental data.

Contribution

It provides a new estimate of the axial contribution to muon g-2 and analyzes the dependence on form factor asymptotics, offering a comprehensive comparison of current approaches.

Findings

Estimated axial contribution: (0.8^{+3.5}_{-0.1})×10^{-11}

Results depend critically on form factor asymptotics

Highlights need for future experiments at high photon virtualities

Abstract

In this work we study the axial contributions to the hadronic light-by-light piece of the muon anomalous magnetic moment using the framework of resonance chiral theory. As a result, we obtain $a_{\mu}^{\textrm{HLbL};A} = \left(0.8^{+3.5}_{-0.1}\right)\cdot 10^{-11}$, that might suggest a smaller value than most recent calculations, underlining the need of future work along this direction. In particular, we find that our results depend critically on the asymptotic behavior of the form factors, and as such, emphasizes the relevance of future experiments for large photon virtualities. In addition, we present general results regarding the involved axial form factors description, comprehensively examining (and relating) the current approaches, that shall be of general interest.