The Discovery Potential of Neutral Supersymmetric Higgs Bosons with Decay to Tau Pairs at the ATLAS Experiment

This work presents a study of the discovery potential for the neutral supersymmetric Higgs bosons h/A/H decaying to tau pairs with the ATLAS experiment at the LHC. The study is based on Monte Carlo samples which are scaled to state-of-the-art cross sections. The analyses are designed assuming an integrated luminosity of 30 1/fb and a center-of-mass energy of sqrt(s) = 14 TeV. The results are interpreted in the m_h^max benchmark scenario. Two final states are analyzed: The dileptonic channel where the two tau leptons decay to electrons or muons and the lepton-hadron channel where one tau decays to an electron or muon and the other tau decays to hadrons. The study of the dilepton channel is based completely on the detailed ATLAS simulation, the analysis of the lepton-hadron channel is based on the fast simulation. The collinear approximation is used to reconstruct the Higgs boson mass and its performance is studied. Cuts are optimized in order to discriminate the signal from background and to maximize the discovery potential given a certain Higgs boson mass hypotheses. In the lepton-hadron channel the selection is split into two analyses depending on the number of identified b-jets. Procedures to estimate the dominant backgrounds from data are studied. The shape and normalization of the Z->tautau background are estimated from Z->ll control regions. The ttbar contributions to the signal regions are estimated from ttbar contr ol regions. The individual analyses are combined and sensitivity predictions are made depending on the Higgs boson mass m_A and the coupling parameter tanb. The light neutral MSSM Higgs bosons with m_A = 150 GeV can be discovered when at least tanb = 11 is realized in nature. The heavy neutral MSSM Higgs bosons with m_A = 800 GeV can be discovered for tanb ≥ 44. However, due to the large width of the reconstructed Higgs boson mass and the mass degeneration, only the sum of at least two of the three Higgs boson signals will be visible.