Search for the Higgs Boson in H->WW Decays at the D0 Experiment and Precise Muon Tracking

This thesis describes the search for the Higgs boson in H->WW(*) decays in proton anti-proton collisions with data taken at the D0 experiment at the Tevatron collider. The data set was taken between April 2002 and September 2003 and has an integrated luminosity of approximately 147 pb^-1. An analysis of the di-muon decay channel of the W pairs was developed which can be scaled to higher luminosities up to the full data set to be taken until 2009 at the Tevatron collider. The number of events observed in the current data set is consistent with expectations from standard model backgrounds. Since no excess is observed, cross-section limits at 95% confidence level for H->WW(*) production have been calculated both standalone and also in combination with other lepton decay channels. The production of W pairs is one major background in the search of H->WW(*) decays. Hence a first measurement of the WW production cross-section with the D0 experiment is presented. Experience gained during this analysis has shown the precise track reconstruction is an essential tool for both measurements. This thesis closes with a contribution to precise tracking in the ATLAS experiment at the future Large Hadron Collider (LHC). An alignment system for ATLAS muon drift chambers at the cosmic ray measurement facility at LMU Munich is presented.