ALP-LEFT Interference and the Muon $(g-2)$

TL;DR

This paper develops a framework to analyze how axion-like particles influence low-energy particle interactions and the muon g-2 anomaly through modifications in the effective field theory's Wilson coefficients.

Contribution

It introduces a comprehensive one-loop calculation of ALP effects on LEFT Wilson coefficients, enabling model-independent low-energy ALP searches and improved muon g-2 predictions.

Findings

Derived full set of ALP-induced source terms for LEFT Wilson coefficients.

Provided improved theoretical predictions for ALP contributions to muon (g-2).

Established a framework for model-independent ALP searches at low energies.

Abstract

The low-energy effective field theory (LEFT) provides the appropriate framework to describe particle interactions below the scale of electroweak symmetry breaking, $\mu_w\sim v$. By matching the Standard Model onto the LEFT, non-zero Wilson coefficients of higher-dimensional operators are generated, suppressed by the corresponding power of $1/v$. An axion or axion-like particle (ALP) with mass $m_a\ll\mu_w$ that interacts with the Standard Model via classically shift-invariant dimension-five operators would also contribute to the LEFT Wilson coefficients, since it can appear as a virtual particle in divergent Green's functions and thus has an impact on the renormalization of the LEFT operators. We present the full set of one-loop ALP-induced source terms modifying the renormalization-group evolution equations of the LEFT Wilson coefficients up to dimension-six order. Our framework allows for model-independent ALP searches at low energies from current bounds on LEFT Wilson coefficients. As a concrete application, we present an improved prediction for ALP effects on the anomalous magnetic moment of the muon.