Large invisible decay of a Higgs boson to neutrinos

TL;DR

This paper explores the possibility that the Higgs boson can decay invisibly into neutrinos within a specific two Higgs doublet model, predicting a significant decay rate and potential observable signatures like displaced vertices.

Contribution

It demonstrates that a sizable invisible decay of the Higgs into neutrinos is possible in a neutrinophilic two Higgs doublet model, with distinctive experimental predictions.

Findings

Higgs decay into neutrinos can have a branching ratio around 0.1 in this model.

The diphoton decay rate is predicted to be about 90% of the SM value.

Displaced vertices may be observed if neutrinos are Majorana particles.

Abstract

We show that the standard model (SM)-like Higgs boson may decay into neutrinos with a sizable decay branching ratio in one well-known two Higgs doublet model, so-called neutrinophilic Higgs model. This could happen if the mass of the lighter extra neutral Higgs boson is smaller than one half of the SM-like Higgs boson mass. The definite prediction of this scenario is that the rate of the SM-like Higgs boson decay into diphoton normalized by the SM value is about 0.9. In the case that a neutrino is Majorana particle, a displaced vertex of right-handed neutrino decay would be additionally observed. This example indicates that a large invisible Higgs boson decay could be irrelevant to dark matter.