Entwicklung von kalorimetrischen Methoden zum Nachweis neuartiger schwerer Teilchen in Proton-Proton Wechselwirkung bei LHC-Energien

The determination of the top quark mass is one of the first tasks of the ATLAS detector at the Large Hadron Collider (LHC) at CERN. In this work, the decay of top anti-top pairs in the semi-leptonic muon channel is investigated. The results of two mass reconstruction methods are compared: the standard analysis and the analysis using a kinematic fit. The resolution functions used in the kinematic fit are validated by measurements with test beams. The result of the kinematic fit is a reduction of the combinatorial background and a significant reduction of the systematic error.