Étude de la production de paires de quarks top avec ATLAS au LHC: mesure de la masse du quark top

Discovered in 1995 at Fermilab, top quark is the last quark discovered. The measurement of its properties allows to test Standard Model predictions and to constrain Higgs boson mass. Due to its properties, the top quark is a privileged partner in the search for New Physics particles expected around TeV scale. This thesis, performed using the ATLAS detector at LHC, describes the different methods developed in order to measure precisely the top quark mass in its semileptonic decay. Two reconstruction methods are presented as well as a dedicated one based on Boosted Decision Trees. Its performances are quantied. The precise measurement of the top quark mass needs a deep understanding of the jet energy scale. This thesis presents two strategies to calibrate light and b jets to the partonic scale. The performance of a kinematical t applied to top mass measurement are presented. A precise measurement of the top quark mass is done using a calibrated scale to the partonic level.