Search for the neutral Higgs Bosons of the Minimal Supersymmetric Standard Model in the tau_lep tau_had decay mode with the ATLAS experiment

This thesis describes the search for the neutral Higgs Bosons of the Minimal Supersymmetric Standard Model. The Higgs boson decay mode considered is the decay into tau leptons with one electron or muon and one hadronically decaying tau lepton in the final state. The p-p collision data analysed have been recorded in 2010 and 2011 with the ATLAS experiment at an centre-of-mass energy of 7 TeV and corresponds to an integrated luminosity of about 4.7/fb.