Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 52: Top quark decay and top properties II

T 52.3: Talk

Wednesday, March 17, 2021, 16:30–16:45, Tb

Study of fake tau leptons in rare top quark production processes using deep neural networks — •Chris M. Staude and Ian C. Brock — Physikalisches Institut, Universität Bonn

Fake tau leptons in Higgs and Z boson decays arise mainly from jets as well as from electrons that mimic the signature of a hadronically decaying tau lepton. QCD events can sometimes appear to be tau lepton decays. This problem is magnified as the cross-section of such QCD events is orders of magnitude higher than our desired production.

In this work, rare top quark production processes where a single top quark is produced in association with a Z boson as well as the associated production with a Higgs boson are investigated.

Deep Neural Networks (DNNs) are used to discriminate real from fake tau leptons using fully labelled simulated events. However, the simulations are often not perfect or have sufficient statistics. Therefore a new method called CWoLa (Classification Without Labels) is also used to differentiate between real and fake tau leptons using only mixtures of events instead of true labels. The classifier is trained on the enriched with fakes tt data and compared to the optimal classifier in the fully-supervised case.