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T: Fachverband Teilchenphysik
T 6: Top Quarks: Production (Exp.) 1
T 6.2: Talk
Monday, March 21, 2022, 16:30–16:45, T-H19
Measurement of the t-channel single top-quark production cross-section in proton-proton collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector — Olga Bessidskaia Bylund1, Dominic Hirschbühl1, •Joshua Reidelstürz1, Mohsen Rezaei Estabragh1, Wolfgang Wagner1, Johannes Erdmann2, and Benedikt Gocke2 — 1Bergische Universität Wuppertal, Wuppertal, Deutschland — 2Technische Universität Dortmund, Dortmund, Deutschland
The measurement of the single top-quark t-channel production cross sections σtq and σtq and their fraction Rt as well as the total cross section σtq,tq is presented. These measurements provide a precise test of the standard model and are sensitive to new-physics phenomena by probing the properties of the Wtb vertex and placing limits on the CKM matrix element |Vtb|. Data taken with the ATLAS detector from 2015 to 2018 corresponding to an integrated luminosity of L= 139 fb−1 at a center-of-mass energy of 13 TeV is analyzed using corresponding samples of simulated events. Requirements are applied to the data selecting events with the signature expected for the signal process. To further enhance the separation between signal and background events a neural network is trained using the Monte Carlo simulated data combining several kinematic variables. The neural network output distribution is then used in a binned profile maximum likelihood fit including all systematic uncertainties to determine the cross sections.