Studies for a Top Quark Mass Measurement and Development of a Jet Energy Calibration with the ATLAS Detector

Jet-Shape-Variables are studied in order to improve the linearity and resolution of the jet energy response. Promising results are shown for Monte Carlo simulation and first √s = 900 GeV proton-proton collision data. Monte Carlo studies for a robust top quark mass measurement in the lepton plus jets decay channel of top quark pair events are performed. Several top quark reconstruction methods are investigated in pseudo-experiments which are equivalent to an integrated luminosity of 200 pb-1 at √s = 10TeV. With a generated top quark mass of mtgen = 172.5 GeV, a value of mt,elMax-pT = 170.4 ± 2.2|stat. ± 8.8|syst. GeV is achieved with the Max-pT reconstruction method in the electron plus jets decay channel.