The Hadronic Light-by-Light Contribution to Muon g-2: A Short Review

TL;DR

This paper reviews recent progress in calculating the hadronic light-by-light scattering contribution to muon g-2, highlighting new estimates and the potential for experimental data to reduce uncertainties.

Contribution

It provides an updated estimate of the hadronic light-by-light contribution to muon g-2 and discusses how low energy two-photon experiments can improve the precision.

Findings

Estimated a^{HLbL}_μ = (10.5 ± 2.6) x 10^{-10}

Recent calculations have refined the contribution estimate

Experimental programs can help reduce model dependence

Abstract

I review the recent calculations and current status of the hadronic light-by-light scattering contribution to muon g-2. In particular, I discuss the main results obtained in a recent work together with Eduardo de Rafael and Arkady Vainshtein where we came to the estimate a^{\rm HLbL}_\mu = (10.5 +- 2.6) x 10^{-10}. How the two-photon physics program of low energy facilities can help to reduce the present model dependence is also emphasized.