Searching for invisible Higgs boson decays at CLIC

In 2012, scientists working at CERN confirmed existence of the Higgs boson, the last missing constituent of the Standard Model (SM). However, this particle is also perceived as a possible key to the discovery of "new physics" Beyond the Standard Model (BSM), connected with the nature of dark matter (DM). Higgs boson decays with emission of invisible DM particles can be the only way to observe connection of SM and BSM sectors. Searches for such decays will be possible at the Compact LInear Collider (CLIC) designed at CERN.

We studied the possibility of measuring invisible Higgs decays with experiment at CLIC running at 380 GeV. Two stage approach is applied to optimise separation between signal and background processes. First a set of preselection cuts is applied to remove background events not consistent with expected signal signature. Then the multivariate analysis methods are applied to optimise significance of observations. We present expected limits on the invisible decays of the SM-like Higgs boson, as well as limits on the dark matter coupling parameter in model with Vector-fermion dark matter.