Search for invisible Higgs bosons produced via vector boson fusion at the LHC using the ATLAS detector

TL;DR

This paper searches for invisible Higgs bosons produced via vector boson fusion at the LHC, aiming to detect potential dark matter candidates, and sets upper limits on their decay branching fraction.

Contribution

It presents the first combined analysis of invisible Higgs decays via VBF at the LHC using data from 2011-2018, establishing new upper limits.

Findings

Observed events align with Standard Model background expectations.

Upper limit on Higgs invisible decay branching ratio is 0.13 at 95% CL.

No significant excess indicating invisible Higgs decays was found.

Abstract

Despite dark matter abundance, its nature remains elusive. Many searches of dark matter particles are carried out using different technologies either via direct detection, indirect detection, or collider searches. In this work, the invisible Higgs sector was investigated, where Higgs bosons are produced via the vector boson fusion (VBF) process and subsequently decay into invisible particles. The hypothesis under consideration is that the Higgs boson might decay into a pair of weakly interacting massive particles (WIMPs), which are candidates for dark matter. The observed number of events are found to be in agreement with the background expectation from Standard Model (SM). Assuming a 125 GeV Higgs boson with SM production cross section, the observed and expected upper limits on the branching fraction of its decay into invisible particles are found to be 0.13 at 95\% confidence level. Combination of searches for an invisibly decaying Higgs boson produced via the main Higgs production modes at the LHC using 2011-2018 data is conducted and discussed.