Combination of searches for invisible Higgs boson decays with the ATLAS detector

The Standard Model (SM) predicts invisible decays of the Higgs Boson via the H->ZZ*->4$\nu$ channel with a branching ratio of ~$10^{-3}$, too small to be testable at the LHC. Several extensions of the SM predict invisible decays of the Higgs to Dark Matter particles. ATLAS is searching for these decays in Vector-Boson-Fusion (VBF) and Higgsstrahlung (ZH, WH) topologies. A statistical combination of searches in the VBF, Z(->leptons)H and V(->hadrons)H channels with 36$\,\text{fb}^{-1}$ of data from the LHC Run 2, as well as a combination with Run 1 data are presented. An upper limit on the invisible branching ratio of the Higgs Boson of 26% ($17^{+7}_{-5}$%) is observed (expected) at a confidence level of 95% in the combination of Run 1 and Run 2 searches.