On the Hadronic light-by-light contribution to the muon $g-2$

TL;DR

This paper reviews the model-based calculations of the hadronic light-by-light contribution to the muon g-2, focusing on pseudo-scalar exchange, pion loops, and potential diagram cancellations, with some new results included.

Contribution

It provides an updated analysis of the hadronic light-by-light contribution to muon g-2, emphasizing model calculations and potential cancellations between diagram types.

Findings

Large cancellation between connected and disconnected diagrams for π^0-exchange

Model calculations highlight the significance of pseudo-scalar exchange

Updated results incorporate recent developments in the field

Abstract

This talk is about the hadronic light-by-light contribution to the muon anomalous magnetic moment, mainly our old work but including some newer results as well. It concentrates on the model calculations. Most attention is paid to pseudo-scalar exchange and the pion loop contribution. Scalar, $a_1$-exchange and other contributions are shortly discussed as well. For the $\pi^0$-exchange a possible large cancellation between connected and disconnected diagrams is expected.