Eta-Correction for Data-Driven Estimate of Non-Prompt Background for Same Charged WW Scattering in the ATLAS Experiment

Vector boson scattering (VBS) provides a unique way to stady the electroweak symmetry breaking anechanisn and further probe the predictions of the Standard Model to possibly discover any hint of new physics beyond the Standard Model. A very promising candidate to study such VBS proceses at the LHC is the $W^{\pm} W^{\pm}$jj-EWK production. Although, it is still significantly susceptible to varions background contributions. One of this background contribution originates from objects which are misidentified as signal leptons, denoted as non-prompt or fake leptons. Thus this thesis further studies the faloe lepton contribution in the $W \pm W \pm j j$-EWK production and aims to improwe the false lepton badkground estimation. Therefore a data driven faloe factor study is conducted for two non-prompet background processes $t \bar{t}$ and $W+j e t s$ using Monte Carlo simulations with truth-level information obtained from PYTHus and MADGRAPH. The processes were simulated for pp-collision in the ATL.AS experiment at a center of mass energy of $\sqrt{s}=13 \mathrm{TeV}$ and an integrated luminosity of $138.7 \mathrm{fb}^{-1}$ in resemblance to the LHC full run 2 data. The dependency of the falke factor fromn the detector region where the object was reconstructed, represented by the posedorapidity $\mathrm{\eta}$, is studied. A control region is used to extract the fake factors binned in $p_T$ respectively $\%$. Furtheranore an additional Tocorrection to the faloe factor, that is calculated in bins of the transverse momentum, is derived for the tE process. A Monte Carbo Closure Test on the Control Region is employed to validate the quality of the faloe lepton badkground estimation. It is found, that the inclusion of the r-dependency improves the fake lepton background estimation for the investigated Monte Carlo samples. This results remain to be valoulated using Monte Carlo samples with a lepton selection solely on reco-level.