Loop-induced h → γγ, Zγ, gg decays in 3-Higgs doublet models

Abstract

In this paper, we analyze the loop-induced decays of neutral Higgs boson [Formula: see text] into pairs of photons, gluons and [Formula: see text] in 3-Higgs Doublet Models (3HDMs), where all the doublets have nonzero vacuum expectation values. In the 3HDM, there are contributions to these decays from loops of charged scalars [Formula: see text] that are not present in the Standard Model. We find an enhancement in the channel [Formula: see text] with respect to the Standard Model prediction in some parameter region while respecting constraints from the measurements of [Formula: see text] at the LHC. The charged Higgs bosons [Formula: see text] lead to the enhancement of [Formula: see text] decay mode in some part of the parameter space of the 3HDM. Then, we discuss the correlations between the decay modes [Formula: see text] and [Formula: see text]. Moreover, we study Type-I and Type-Z of 3HDMs and find that these types of 3HDMs can be distinguished via only the gluonic decays, since the contributions of the [Formula: see text] loops are dominant to those of fermion loops. We also investigate the effects of the model parameters on these loop-induced decays. As an interesting phenomenological consequence, the 3HDM is dominantly governed by the parameters: two ratios of vacuum expectation values (VEVs); [Formula: see text], [Formula: see text] and the mixing angles of the CP-even Higgs bosons, [Formula: see text] and [Formula: see text].