Supersymmetry Searches in the Single Lepton Final State with the ATLAS Detector

This thesis presents an analysis for the search of Supersymmetry with the ATLAS detector at the LHC. The final state with one lepton, several coloured particles and large missing transverse energy was chosen. Particular emphasis was placed on the optimization of the requirements for lepton identification. This optimization showed to be particularly useful when combining with multi-lepton selections. The systematic error associated with the higher order QCD diagrams in Monte Carlo production is given particular focus. Methods to verify and correct the energy measurement of hadronic showers are developed. Methods for the identification and removal of mismeasurements caused by the detector environment are applied. A new detector simulation system is shown to provide good prospects for future fast Monte Carlo production. The analysis was performed for 35 $pb^{−1}$ and no significant deviation from the Standard Model is seen. Exclusion limits are found in the single muon and four jets subchannel for minimal Supergravity. Previous limits set by Tevatron and LEP are extended.