Higgs production in Vector Boson Fusion in the H → ττ → ll+4ν final state with ATLAS: a sensitivity study

A study of the expected sensitivity of the ATLAS experiment to discover the Standard Model Higgs boson produced via vector boson fusion (VBF) and its decay to H → ττ → ll+4ν is presented. The study is based on simulated proton-proton collisions at a centre-of-mass energy of 14 TeV. For the rst time the discovery potential is evaluated in the presence of additional proton-proton interactions (pile-up) to the process of interest in a complete and consistent way. Special emphasis is placed on the development of background estimation techniques to extract the main background processes Z → ττ and tt production using data. The tt background is estimated using a control sample selected with the VBF analysis cuts and the inverted b-jet veto. The dominant background process Z → ττ is estimated using Z → μμ events. Replacing the muons of the Z → μμ event with simulated -leptons, Z → ττ events are modelled to high precision. For the replacement of the Z boson decay products a dedicated method based on tracks and calorimeter cells is developed. Without pile-up a discovery potential of 3σ to 3.4σ in the mass range 115 GeV < MH < 130 GeV is obtained assuming an integrated luminosity of 30 fb¹. In the presence of pile-up the signal sensitivity decreases to 1.7σ to 1.9 σ mainly caused by the worse resolution of the reconstructed missing transverse energy.