Search for invisibly decaying vector boson fusion produced Higgs bosons with 139 fb$^{-1}$ of $pp$ collisions with the ATLAS detector

While the Standard Model (SM) predicts a branching ratio of the Higgs boson decaying to invisible particles of O(0.001), the current measurement of the Higgs boson coupling to other SM particles allows for up to 30% of the Higgs boson width to originate from decays beyond the SM (BSM). The small SM-allowed rate of Higgs boson decays to invisible particles can be enhanced if the Higgs boson decays into a pair of weakly interacting massive particles (WIMPs), which may explain the nature of dark matter. The Vector Boson Fusion (VBF) production mechanism of the Higgs boson provides a distinctive signature with two forward jets that are largely separated in pseudorapidity leading to a large invariant mass that can be used to target events with invisible Higgs decays, where particles invisible to the detector are a source of missing transverse energy. The most recent results using the ATLAS detectors at the LHC of VBF-produced Higgs bosons decaying invisibly are presented, utilizing the full Run-2 dataset of 139 fb$^{-1}$ of 13 TeV center-of-mass proton--proton collisions. Further interpretations set limits on the VBF production of other heavy scalars, and the WIMP-nucleon elastic scattering cross-section.