New Limits on Exotic Muon Interactions Mediated by Axion-Like Particles

Abstract

The precise measurement of the muon anomalous magnetic moment $a_μ$ provides a sensitive probe of exotic interactions between muons mediated by light beyond the Standard Model (BSM) bosons. Recent advances in both experiment and theory have largely reconciled the long-standing discrepancy in $a_μ$. Using the latest result, $Δa_μ= a^{\rm exp}_μ- a^{\rm SM}_μ= (38 \pm 63) \times 10^{-11}$, we derive updated limits on light BSM boson-mediated exotic muon interactions.

Figures (1)

• Figure 1: Constraints on exotic spin-dependent interactions involving muons at $95\%$-CL. The gray regions indicate the excluded parameter space. $\lambda = \hbar / (m_{\phi,X} c)$ represents the interaction range, where $\hbar$ is Planck’s constant and $c$ is the speed of light. (a) Constraints on scalar-particle-mediated exotic interactions. The red dotted line represents the result from Ref. yan2019. (b) Constraints on vector-particle-mediated exotic interactions. Constraints on the SS and PP couplings from SN1987A are taken from Ref. Caputo2022PRD, while the VV coupling constraint is from Ref. Croon2021JHEP.