SMuK 2023 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 3: Top I
T 3.2: Vortrag
Montag, 20. März 2023, 16:45–17:00, HSZ/0401
Search for same-sign top pair production with the Standard Model Effective Field Theory at the ATLAS experiment — Noemi Cavalli1,2, Merve Nazlim Agaras4, Maximiliano Sioli2, Matteo Negrini2, Kevin Alexander Kroeninger1, Shalini Epari4, Aurelio Juste Rozas Rozas4, Stergios Kazakos4, Javier Montejo Berlingen3, Nicola Orlando4, Tamara Vazquez Schroeder3, and •Aaron van der Graaf1,2 — 1TU Dortmund — 2Bologna — 3CERN — 4IFAE
Model-independent searches for new physics at high energies by using the Standard Model (SM) Effective Field Theory (SMEFT) are an important part of todays physics program. Same-sign top-quark pair production is highly suppressed in the SM while several models beyond the SM enhance the production. SMEFT is used obtain model-independent predictions for the production of the same-sign top pairs beyond the SM. Three EFT operators are considered to simulate the searched signal. The full Run 2 dataset collected by the ATLAS detector from proton-proton collisions is used for this search for same-sign top-quark pairs, in the dilepton final state. A Neural Network (NN) is employed to build separate signal regions (SR) enriched in same-sign top events resulting from different EFT operators. Within the defined SRs, a second NN is applied to perform a signal-background discrimination. In order to attain an accurate estimation of background contributions in the SRs, several Control Regions (CRs) are defined. The background estimation and the signal search are performed by using a maximum likelihood fit over all analysis regions.