Observing an invisible Higgs boson
O. J. P. Eboli, D. Zeppenfeld
TL;DR
The paper addresses the challenge of detecting an invisibly decaying Higgs at the LHC by exploiting weak boson fusion, leveraging forward-jet tagging and central jet veto to suppress backgrounds. It presents a data-driven approach to background normalization using leptonic Vjj samples and quantifies sensitivities, showing that Br(H→invisible) can be constrained to about 13% with 10 fb^{-1} and that a Higgs with Br inv ≈ 1 could be discovered up to m_H ≈ 480 GeV in 10 fb^{-1}. With 100 fb^{-1}, reach improves substantially, extending mass reach while maintaining control over systematics. Overall, the WBF channel potentially surpasses Zh and ttH channels for invisible Higgs decays and provides concrete trigger strategies for LHC experiments.
Abstract
Given its weak coupling to bottom quarks and tau leptons, the Higgs boson may predominantly decay into invisible particles like gravitinos, neutralinos, or gravitons. We consider the manifestation of such an invisibly decaying Higgs boson in weak boson fusion at the CERN LHC. Distinctive kinematic distributions of the two quark jets of the signal as compared to Zjj and Wjj backgrounds allow to restrict the Higgs branching ratio to 'invisible' final states to some 13% with 10fb^{-1} of data, provided events with two energetic forward jets of high dijet invariant mass and with substantial missing transverse momentum can be triggered efficiently. It is also possible to discover these particles with masses up to 480 GeV in weak boson fusion, at the 5 sigma level, provided their invisible branching ratio is close to 100%.