Evidence for Higgs boson decays to τ leptons

The Higgs boson discovery in 2012 was based primarily on the analyses of Higgs boson decays to vector bosons. In the Standard Model (SM) the fermions acquire their masses via Yukawa couplings to the Higgs field, and therefore it was of fundamental importance to also confirm Higgs boson decays to fermions. In spite of significant experimental challenges, this was eventually achieved in the analyses of ττ final states. Using the full LHC Run 1 data set, ATLAS and CMS established H → ττ signals with local significances above three standard deviations and with properties consistent with SM predictions. These results provided the first evidence for a direct coupling of the 125 GeV Higgs boson to fermions.