Mesure de l’efficacité d’identification des électrons et recherche de SUSY dans le canal 2 leptons avec le détecteur ATLAS

ATLAS experiment at LHC has, during this three operating years, open access to energy of the order of magnitude of the TeV. In this context, the work has been devoted to the study of the detector performance and the analysis of the data collected. In this thesis, the first part is dedicated to the measure of the electron identification efficiency. Details of the measurement method and first results in two dimensions are presented. The second part shows the search for Supersymmetry in the 2 lepton channel. The full 2012 dataset allows to exclude charginos with a mass lower than 180 GeV in the hypothesis of a massless neutralino.