SMuK 2023 – scientific programme

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T: Fachverband Teilchenphysik

T 133: Top, EW II

T 133.5: Talk

Thursday, March 23, 2023, 18:30–18:45, HSZ/0103

Differential cross-section measurements of an hadronically decaying top-quark-antitop-quark pair produced in association with two b-jets with the ATLAS detector at √s = 13 TeV — •Nina Wenke and Teresa Barillari — Max-Planck-Institut für Physik, München

The production of a top-quark-antitop-quark (tt) pair in association with two b-jets (ttbb) is an important and insightful Standard-Model (SM) process to study at the LHC. It is the perfect playground to study the dynamics of multiple heavy quark production which is difficult to model precisely. It is also a major background in important SM measurements. In addition, precise ttbb measurements could allow to catch glimpses of New Physics.
In this talk, preliminary results of the first ATLAS analysis targeting the hadronic decay channel of ttbb production will be presented. It uses proton-proton collision-data recorded with the ATLAS detector at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 139 fb⁻¹. The analysis uses a cut-based event selection with at least four b-jets. A likelihood-based algorithm is then used to reconstruct the hadronic decay of the tt pair in the event. The challenging large multijet background is modelled using a data-driven method. The final aim of the analysis is to perform fiducial differential cross-section measurements as a function of several variables and compare them to next-to-leading-order matrix-element calculations matched to a parton shower.