%0 Thesis
%A Draeger, Arne-Rasmus
%T Prediction of the \textt―\textt and \textW+\textJets Background in a Search for New Physics with Jets and Missing Transverse Energy at CMS
%N DESY-THESIS-2016-005
%@ 1435-8085
%I Universität Hamburg
%V Dissertation
%C Hamburg
%M PUBDB-2016-01240
%M DESY-THESIS-2016-005
%B DESY-THESIS
%P 261
%D 2016
%Z Dissertation, Universität Hamburg, 2016
%X One of the primary goals of the LHC is the search for physics beyond the Standard Model (SM). Among the most studied extensions of the SM is supersymmetry (SUSY), which postulates a symmetry between fermions and bosons and requires the introduction of a SUSY partner particle for every SM particle. At the LHC the production of colored SUSY particles (squarks ~\textq and gluinos ~\textg) can have a significant cross section, leading to distinct signatures. These particles decay to lighter new particles typically emitting quarks and gluons. Furthermore, the lightest SUSY particle is often assumed to be stable and only weakly interacting, hence it escapes the detector and leads to missing transverse energy.<br />In this thesis, a search for such new particles with proton-proton collision data recorded at the CMS experiment at √s=8 \textTeV, corresponding to an integrated luminosity of 19.5 \textfb<sup>−1</sup>, which is performed in the final states with jets, missing transverse momentum, and no isolated muons or electrons. All SM background contributions are determined from data. A major background contribution arises from \textt―\textt and \textW+\textJets events where a W boson decays into an electron or muon which is not identified in the detector, referred to as "lost-lepton". Such events contribute to the search selections if the muons and electrons are unidentified, here denoted as "lost-leptons". The main focus of this thesis is on the development and validation of a method to estimate the amount of lost-lepton events using a single-lepton control sample from data.<br />The number of observed events are found to be consistent with the SM background expectation. Upper exclusion limits on SUSY particle masses are derived in different simplified models of ~\textg and ~\textq pair production. The production of light-flavor ~\textq below a mass of 780 GeV and ~\textg with masses below 1.1-1.2 TeV  are excluded at 95% confidence level. Furthermore, the lost-lepton prediction method is refined for the application to the new LHC data at √s=13 \textTeV , and the performance of the relevant physics object reconstruction is demonstrated using the first 42 \textpb<sup>−1</sup> of √s=13 \textTeV data.
%F PUB:(DE-HGF)3 ; PUB:(DE-HGF)29 ; PUB:(DE-HGF)11
%9 BookReportDissertation / PhD Thesis
%R 10.3204/DESY-THESIS-2016-005
%U https://bib-pubdb1.desy.de/record/295971