Aachen 2019 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

T: Fachverband Teilchenphysik

T 36: Supersymmetrie I

T 36.5: Talk

Tuesday, March 26, 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=(m_t1−m_χ1⁰), 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.