Aachen 2019 – wissenschaftliches Programm
T 36.5: Vortrag
Dienstag, 26. März 2019, 17:00–17:15, S11
QCD background estimation for the search of top squarks with 1-lepton in the final state with ATLAS — •Arrubarrena Paola, Handl David, and Wagner-Kuhr Jeannine — LMU, Munich, Germany
Supersymmetry (SUSY) is an extension of the standard model of particle physics which predicts a supersymmetric partner for each particle in the standard model. If R-parity is conserved, then the lightest supersymmetric particle (LSP) is stable and a good dark matter candidate. In many models the LSP is favored to be the lightest neutralino (χ10), and the SUSY partner of the top quark, top squark (t1), is usually assumed to be light and in the reach of the LHC. In this talk studies on QCD multijet background estimation for the full Run-2 analysis, using pp collision data at a center of mass energy of 13 TeV recorded with the ATLAS detector from 2015 to 2018, are presented.
In this analysis, QCD multijet background originates from jets or non-prompt leptons that mimic the isolated lepton criteria and hence are wrongly selected. In particular for signal regions targeting small Δ m=(mt1−mχ10), which are characterized by low-energy leptons, the QCD background is expected to be larger and a quantitative evaluation of the QCD background in these regions is essential. In this talk the estimation of the QCD multijet background via a data-driven fake-factor method is presented.