Probing for invisible Higgs decays with global fits

A bstract We demonstrate by performing a global fit on Higgs signal strength data that large invisible branching ratios (Br inv ) for a Standard Model (SM) Higgs particle are currently consistent with the experimental hints of a scalar resonance with mass m h ~ 124 GeV. For this mass, we find Br inv < 0 . 64 (95% CL) from a global fit to individual channel signal strengths supplied by ATLAS, CMS and the Tevatron collaborations. Novel tests that can be used to improve the prospects of experimentally discovering the existence of a Br inv with future data are proposed. These tests are based on the combination of all visible channel Higgs signal strengths, and allow us to examine the required reduction in experimental and theoretical errors in this data that would allow a more significantly bounded invisible branching ratio to be experimentally supported. We examine in some detail how our conclusions and method are affected when a scalar resonance at this mass scale has couplings deviating from the SM ones.