# Axion-like particles, lepton-flavor violation and a new explanation of $a_\mu$ and $a_e$

## TL;DR

This paper explores how axion-like particles with lepton-flavor violating couplings can be detected through exotic decays and proposes new explanations for the muon and electron magnetic moment anomalies.

## Contribution

It introduces a novel framework for ALPs with lepton-flavor violation to explain magnetic moment anomalies and analyzes experimental sensitivities across different decay channels.

## Key findings

- Resonant production enhances sensitivity of three-body decays
- Exotic decay searches are highly complementary to radiative decay searches
- Allowing multiple couplings provides new explanations for magnetic moment anomalies

## Abstract

Axion-like particles (ALPs) with lepton-flavor violating couplings can be probed in exotic muon and tau decays. The sensitivity of different experiments depends strongly on the ALP mass and its couplings to leptons and photons. For ALPs that can be resonantly produced, the sensitivity of three-body decays such as $\mu\to 3e$ and $\tau\to 3\mu$ exceeds by many orders of magnitude that of radiative decays like $\mu\to e\gamma$ and $\tau\to\mu\gamma$. Searches for these two types of processes are therefore highly complementary. We discuss experimental constraints on ALPs with a single dominant lepton-flavor violating coupling. Allowing for one or more such couplings offers qualitatively new ways to explain the anomalies related to the magnetic moments of the muon and electron.