Probing axion-like particles in leptonic decays of heavy mesons

TL;DR

This paper investigates the potential for detecting axion-like particles (ALPs) through leptonic decays of heavy mesons, analyzing different coupling scenarios and deriving constraints from experimental data to predict decay limits.

Contribution

It introduces a comprehensive analysis of ALP couplings in heavy meson decays and provides new constraints and predictions using the Bethe-Salpeter method.

Findings

Constraints on ALP coupling strengths from meson decay data

Predicted upper limits for $B_c^-$ meson decay processes involving ALPs

Different coupling scenarios analyzed for their impact on decay rates

Abstract

We study the possibility of finding the axion-like particles (ALPs) through the leptonic decays of heavy mesons. The Standard Model (SM) predictions of the branching ratios of the leptonic decays of heavy mesons are less than the corresponding experimental upper limits. This provides some room for the existence of decay channels, of which the ALP is one of the products. Three scenarios are considered: First, the ALP is only coupled to one single charged fermion, namely, the quark, the antiquark, or the charged lepton; second, the ALP is only coupled to quark and antiquark with the same strength; and third, the ALP is coupled to all the charged fermions with the same strength. The constraints of the coupling strength in different scenarios are obtained by comparing the experimental data of the branching ratios of leptonic decays of $B^-$, $D^+$, and $D_s^+$ mesons with the theoretical predictions achieved by using the Bethe-Salpeter (BS) method. These constraints are further applied to predict the upper limits of the leptonic decay processes of the $B_c^-$ meson in which the ALP participates.