Search for invisible decays of a Higgs boson using vector-boson fusion in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

TL;DR

This paper reports a search for invisible decays of the Higgs boson produced via vector-boson fusion at 8 TeV, setting limits on the decay rate and constraining dark matter models in collider data.

Contribution

First search for Higgs to invisible decays via vector-boson fusion at 8 TeV with ATLAS, providing new bounds on dark matter interactions.

Findings

Upper limit of 0.28 on Higgs invisible branching fraction

Constraints on dark matter-nucleon scattering cross section

Comparison with direct detection experiment results

Abstract

A search for a Higgs boson produced via vector-boson fusion and decaying into invisible particles is presented, using 20.3 fb$^{-1}$ of proton--proton collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the LHC. For a Higgs boson with a mass of 125 GeV, assuming the Standard Model production cross section, an upper bound of 0.28 is set on the branching fraction of $H\to$ invisible at 95% confidence level, where the expected upper limit is 0.31. The results are interpreted in models of Higgs-portal dark matter where the branching fraction limit is converted into upper bounds on the dark-matter--nucleon scattering cross section as a function of the dark-matter particle mass, and compared to results from the direct dark-matter detection experiments.