The ALP explanation to muon $(g-2)$ and its test at future Tera-$Z$ and Higgs factories

TL;DR

This paper explores how an Axion Like Particle (ALP) could explain the muon g-2 anomaly, analyzing current constraints and proposing future collider tests at Tera-Z and Higgs factories.

Contribution

It provides a detailed 2-loop level analysis of ALP couplings to gauge bosons and assesses the potential of future colliders to test the ALP explanation for muon g-2.

Findings

Current experiments do not exclude the ALP explanation for muon g-2.

Future Tera-Z and Higgs factories can fully probe the relevant ALP parameter space.

Specific final states at future colliders can effectively test the ALP hypothesis.

Abstract

Models with an Axion Like Particle (ALP) can provide an explanation for the discrepancy between experimental measurement of the muon anomalous magnetic moment $(g-2)_\mu$ and the Standard Model prediction. This explanation relies on the couplings of the ALP to the muon and the photon. We also include more general couplings to the electroweak gauge bosons and incorporate them in the calculations up to the 2-loop order. We investigate the existing experimental constraints and find that they do not rule out the ALP model under consideration as a possible explanation for the $(g-2)_\mu$ anomaly. At the same time, we find the future Tera-$Z$ and Higgs factories, such as the CEPC and FCC-ee, can completely cover the relevant parameter space through searches with final states $(\gamma \gamma) \gamma$, $(\mu^+ \mu^-) \gamma$ and $(\mu^+ \mu^-) \mu^+ \mu^-$.