Würzburg 2018 – scientific programme

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T: Fachverband Teilchenphysik

T 3: Higgs I

T 3.2: Talk

Monday, March 19, 2018, 16:15–16:30, Philo-HS3

Tau Identification and Search for SM H→ττ with ATLAS — •Théo Megy, Lei Zhang, and Karsten Köneke — Albert-Ludwigs-Universität Freiburg

The decay of a Higgs boson into a pair of tau leptons is the most privileged channel in order to access Higgs boson couplings to leptons. The run 1 analysis in ATLAS reached an evidence for this process of 4.5σ, and the observation was reached by combining this result with CMS’s. The aim is now to rediscover this process at 13 TeV with ATLAS. For this three final states, depending on the tau decay, are to be investigated. The semi-leptonic channel, in which the two tau leptons decay leptonically and hadronically respectively, is considered here.
An identification algorithm is used to select the hadronically decaying tau lepton, and suppress background events containing a jet faking a tau lepton. The analysis is therefore sensitive to the precise knowledge of the identification efficiency of tau leptons. The impact of the use of different identification working points on the analysis will be discussed.
The possibility to use continuous tau identification in order to increase the sensitivity of the analysis will be introduced. The goal is to split the cut-based analysis signal region into several identification sub-regions. New identification working points are necessary for this, and as a consequence new scale factors need to be measured. The introduction of a flattened BDT might be helpful to define optimal working points. The use the continuous tau identification is also considered in the multivariate analysis.