Muon (and Lepton) Anomalous Magnetic Moments and Limits on Their Radii

TL;DR

This paper uses limits on lepton radii and contact interactions to set bounds on deviations in lepton magnetic moments, finding the tightest constraints for taus and competitive ones for electrons and muons.

Contribution

It introduces a method to derive limits on lepton magnetic moment deviations from radius and contact interaction constraints, improving bounds especially for taus.

Findings

Tightest limits for tau magnetic moments.

Stronger bounds for electrons than low energy measurements.

Competitive bounds for muons compared to recent experiments.

Abstract

The limits on lepton radii and contact interaction scales are used to derive limits on the deviations of lepton anomalous magnetic dipole moments (g-2)/2 from the Standard Model predictions. In the case of quadratic dependence of the deviations on the lepton mass the limits for electrons are better compared to low energy measurements, for muons somewhat weaker than the latest precision experiments, and for taus by far the best.