Bonn 2020 – scientific programme

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T: Fachverband Teilchenphysik

T 28: Top quarks: mass and jets

T 28.1: Talk

Tuesday, March 31, 2020, 17:00–17:15, H-HS XI

Investigation of the top-quark mass precision using machine-learning techniques at the ATLAS experiment — •Steffen Ludwig, Andrea Knue, and Gregor Herten — University of Freiburg, Institute of Physics

The top quark is the heaviest known elementary particle in the Standard Model (SM) and its mass is a fundamental parameter. Its value is close to the scale of electroweak symmetry breaking and hence the top quark might serve as a window to physics beyond the SM.

Due to the high collision rate of the LHC, the ATLAS collaboration was able to measure the top-quark mass at subpercent level at √s = 8 TeV. Removing badly reconstructed events has shown to reduce the dominant signal modelling uncertainties using tt events in the lepton + jets channel.

Exploring this decay channel using pp collision data at √s = 13 TeV, the talk focuses on the influence of deep neural networks for event reconstruction in comparison to a likelihood-based reconstruction algorithm (KLFitter) on the event reconstruction efficiency and purity, while studying the impact on the systematic uncertainties on the top-quark mass measurement.