Light axion-like particle and rare Higgs decays

Rare and exotic decay modes of the Higgs boson are one kind of interesting decay processes, which can be used as a tool to further test the SM and search for new physics phenomena. In this paper, considering the constraints on the [Formula: see text] coupling from the relevant LHC data, we calculate the contributions of the light axion-like particle (ALP) with mass less than 200[Formula: see text]MeV to the rare Higgs decays [Formula: see text], [Formula: see text] and [Formula: see text]. Our numerical results show that the light ALP can indeed generate significantly contributions to these decay processes. The value of the branching ratio [Formula: see text] induced only by ALP is larger than the SM prediction at least one order of magnitude. We expect that our results might be helpful to test the indirect signals of light ALP in near future collider experiments, particularly in future lepton collider experiments.