Mise en oeuvre de l'étiquetage des jets issus de quarks beaux dans l'expérience ATLAS au LHC

The Standard Model of particle physics predicts the existence of the Higgs boson, which preferentially decays to b quark pairs at low mass. The identification of jets stemming from such quarks in the ATLAS detector, placed at the LHC, is thus one of the keys to modern particle physics. In this document, an overview of the b-tagging methods used in ATLAS as well as the optimization of a specific algorithm, JetProb, are presented. The preparation to the measurement of these algorithms efficiency in data is also developed. Finally, after the first data taking at 900 GeV and then at the record energy of 7 TeV in 2009-2010, the first results on charged track studies and b-tagging commissioning were obtained and are gathered together here. Comparison with simulation shows a good agreement and the first b-jet and top events candidates are studied.