Würzburg 2018 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 57: Higgs III
T 57.8: Vortrag
Mittwoch, 21. März 2018, 18:15–18:30, Z6 - HS 0.004
Search for lepton-flavour violating decays of the Higgs-boson using the asymmetry method with the ATLAS experiment at √s=13 TeV — •Katharina Schleicher1, Duc Bao Ta2, and Markus Schumacher1 — 1Albert-Ludwigs-Universität Freiburg — 2Johannes Gutenberg-Universität Mainz
One interesting topic after the discovery of the Higgs-boson is the search for lepton-flavour violating (LFV) couplings. These are predicted in several models, including supersymmetric extensions of the standard model (SM) and the general two-higgs-dublet model. In nature, LFV was already observed in form of neutrino oscillations.
Possible LFV decays in the Higgs-sector are H→ eµ, H→τ e and H→τµ. In this analysis only the decays of H→τ e and H→τµ with leptonic τ-decays leading to eµ+X final states are considered. For background estimation the asymmetry method is utilized. It exploits two facts. First, SM backgrounds with prompt leptons are symmetric w.r.t. a replacement of electrons with muons and vice versa. And second, this symmetry is broken when assuming that the branching ratios of the two considered LFV decays are of different orders of magnitude.
One challenge is to maintain this symmetry despite experimental differences of electrons and muons. Another challenge is to enhance the sensitivity. Therefore, a multivariate analysis is developed by training boosted decision trees.
The analysis is performed on the full 2015 and 2016 run-2 data set in proton-proton collisions (L=36.07 fb−1) taken with the ATLAS detector at √s=13 TeV.