Measurement of the mumu Background for Neutral MSSM Higgs Searches with the ATLAS Detector

The subject of this work is the development of a data-driven method for the background estimation for neutral MSSM Higgs searches in the decay channel h/H/A -> mumu. The method employs signal-free control samples from the ee and emu final states and is based on the vanishing decay rate h/H/A -> ee. In contrast, for the background processes the decay rates into electrons and muons are equal at particle level. Differences between the electron and muon final states at reconstruction level arising from the detector response and the presence of Bremsstrahlung and final state radiation are studied in detail. The accuracy of the method is evaluated for the dominant background contributions from Z boson and tt decays. Detector-related systematic uncertainties concerning muon, electron and jet reconstruction are taken into account. Finally, the presented method for the background estimation is used to evaluate the exclusion limits at a confidence level of 95%.