Karlsruhe 2024 – scientific programme
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T: Fachverband Teilchenphysik
T 126: Top physics 5 (top mass)
T 126.3: Talk
Friday, March 8, 2024, 09:30–09:45, Geb. 30.95: Audimax
Towards the simultaneous extraction of the top-quark mass and decay width using bb4ℓ predictions — Diptaparna Biswas1, Beatrice Cervato1, Markus Cristinziani1, Carmen Diez Pardos1, Ivor Fleck1, Arpan Ghosal1, Gabriel Gomes1, Jan Joachim Hahn1, Vadim Kostyukhin1, Nils Krengel1, Buddhadeb Mondal1, Stefanie Müller1, •Katharina Voss1, Wolfgang Walkowiak1, Adam Warnerbring1, and Tongbin Zhao1,2 — 1Experimentelle Teilchenphysik, Center for Particle Physics Siegen, Universität Siegen — 2Shandong University, China
We present the first dedicated measurement aimed at the simultaneous extraction of the top-quark mass and decay width, which are two closely related input parameters in high-precision theoretical predictions. Previous top-quark decay width measurements were performed for a fixed top-quark mass value and a dependence of the decay width on the assumed mass value in the extraction was observed.
The sensitive observable used in the measurement is the mℓ b distribution obtained from top-quark pair production events in the dileptonic eµ decay channel of the full Run-2 √s=13 TeV ATLAS dataset. Since especially in the tt/tW interference region a high sensitivity to the top-quark decay width was observed, an accurate description of this phase space region is essential for the parameter extraction. This can be achieved with the bb4ℓ POWHEG generator. Studies of the systematic uncertainties related to the use of the bb4ℓ generator will be presented, which is of central importance to have a reliable estimate of the modelling uncertainties influencing the measurement.
Keywords: Top quark mass; Top quark decay width; bb4l generator; Top Modelling; Modelling uncertainties