Radiative decays ZH → ViZ (Vi = γ, Z) in little Higgs models

Abstract

The study of the phenomenology of an extra neutral gauge boson, ZH, can help us to unravel the underlying theory. We study the decay of such a particle into two neutral gauge bosons, ZH → ViZ (Vi = γ, Z), in two popular versions of the little Higgs model: the littlest Higgs model and the simplest little Higgs model. These decays are induced at the one-loop level by a fermion triangle and are interesting as they are strongly dependent on the mechanism of anomaly cancellation. All the relevant tree-level two- and three-body decays of the ZH gauge boson are also calculated. It is found that the branching ratios for the ZH → γZ decays can be as large as that of a tree-level three-body decay but the ZH → ZZ decay is very suppressed. We also discuss the experimental prospects for detecting these decays at the Large Hadron Collider and a future linear collider. We conclude that the latter would offer more chances for the detection of such rare decays.