The Anomalous Magnetic Moment of the Muon: Beyond the Standard Model via Chiral Enhancement

TL;DR

This paper explores explanations for the muon's anomalous magnetic moment discrepancy involving heavy new particles with chiral enhancement, predicting effects in Higgs and Z-boson decays, and examines leptoquark models as a specific case.

Contribution

It introduces a framework for explaining the muon g-2 anomaly through chiral enhancement in heavy new physics, including detailed analysis of leptoquark models.

Findings

Chirally enhanced new physics can account for the muon g-2 anomaly.

Predicted effects in Higgs and Z decays depend on new particles' representations.

Leptoquark models provide a concrete realization of the proposed mechanism.

Abstract

The anomalous magnetic moment of the muon displays a $4.2\sigma$ tension with the Standard-Model prediction, if $e^+e^-\to \text{hadrons}$ data are used for hadronic vacuum polarization. In these proceedings we review possible explanations of this anomaly in terms of heavy new particles. As the necessary effect is of the order of the electroweak Standard-Model contribution, viable explanations with TeV-scale physics must involve an enhancement factor; in particular, one can obtain the chirality flip of the dipole operator via a sizable coupling to the Higgs doublet instead of the small muon Yukawa coupling. Such Standard-Model extensions then also predict effects in Higgs and $Z$-boson decays to muons, with details depending on the $SU(2)_L\times U(1)_Y$ representations of the new particles. We first review the general case of chirally enhanced new physics, before discussing in more detail the concrete example of leptoquark models.