Motivation and detectability of an invisibly-decaying Higgs boson at the Fermilab Tevatron

TL;DR

This paper explores the potential for detecting an invisibly-decaying Higgs boson at the Fermilab Tevatron, emphasizing the importance of considering invisible decay channels in future searches and analyzing their experimental signatures.

Contribution

It introduces the idea of searching for an invisibly-decaying Higgs at the Tevatron and evaluates the experimental sensitivity and strategies for such detection.

Findings

Tevatron can observe a 125 GeV invisibly-decaying Higgs with 30 fb^{-1}

Invisible decay channels significantly affect Higgs search strategies

Analysis of dilepton and missing energy channels for Higgs detection

Abstract

A Higgs boson with mass below 150 GeV has a total decay width of less than 20 MeV into accessible Standard Model states. This narrow width means that the usual branching fractions for such a light Higgs boson are highly susceptible to any new particles to which it has unsuppressed couplings. In particular, there are many reasonable and interesting theoretical ideas that naturally imply an invisibly-decaying Higgs boson. The motivations include models with light supersymmetric neutralinos, spontaneously broken lepton number, radiatively generated neutrino masses, additional singlet scalar(s), or right-handed neutrinos in the extra dimensions of TeV gravity. We discuss these approaches to model building and their implications for Higgs boson phenomenology in future Tevatron runs. We find, for example, that the Tevatron with 30 fb^{-1} integrated luminosity can make a 3\sigma observation in the l+ l- plus missing transverse energy channel for a 125 GeV Higgs boson that is produced with the same strength as the Standard Model Higgs boson but always decays invisibly. We also analyze the b anti-b plus missing transverse energy final state signal and conclude that it is not as sensitive, but it may assist in excluding the possibility of an invisibly-decaying Higgs boson or enable confirmation of an observed signal in the dilepton channel. We argue that a comprehensive Higgs search at the Tevatron should include the possibility that the Higgs boson decays invisibly.