Investigations on the decay length method for the measurement of the top quark mass at the Atlas experiment

The precision of the determination of the top quark mass at particle collider experiments with methods which rely on jet energy measurements is limited due to the jet energy scale. This thesis presents a method that relies almost exclusively on tracking and thus has complementary uncertainties with respect to other methods. This so-called decay length method correlates the mean transverse decay length of B-Hadrons originating from top quark decays to the mass of the initial top quark. The thesis discusses the application the method for the semileptonic decay channel of tt-Events at the ATLAS detector and presents an estimate for uncertainties based on MonteCarlo simulations.