Status of hadronic light-by-light scattering and the muon $(g-2)$

TL;DR

This paper reviews recent progress in calculating the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment, highlighting the main pseudoscalar contribution and its implications for the current discrepancy between theory and experiment.

Contribution

It provides an updated numerical estimate of the hadronic light-by-light contribution, emphasizing the role of experimental data and recent computational advances.

Findings

Estimated a_mu^HLBL = (12.1 ± 3.0) × 10^(-10)

Current calculations suggest a 4σ deviation from experimental results

Highlights the importance of pseudoscalar contributions in the analysis

Abstract

In this talk we review the recent progress on the numerical determination of the Hadronic Light-by-Light contribution to the anomalous magnetic moment of the muon and we discuss the role of experimental data on the accuracy of its determination. Special emphasis on the main contribution, the pseudoscalar piece, is made. Gathering recent progress in the light-by-light scattering contribution we consider $a_{\mu}^{{\mathrm{HLBL}}} = (12.1\pm3.0)\times10^{-10}$ as a good summary of the state-of-the-art calculations which still claims for a $4\sigma$ deviation between theory and experiment for the $(g-2)_{\mu}$.