Search for Neutral MSSM Higgs Bosons Decaying to ${\tau}_{had} {\tau}_{had}$ in $\sqrt{s}$ = 7 TeV Proton–Proton Collisions with the ATLAS Detector

In this thesis a search for the neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) in the h/A/H -> tau_had tau_had decay channel is described. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb^-1. Final states with two hadronic tau-lepton decays requiring either the presence or absence of b-jets are considered and the selection is optimised for Higgs bosons in b-quark associated and gluon-fusion production. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived in combination with the h/A/H -> mu mu, h/A/H -> tau_e tau_mu and h/A/H -> tau_lep tau_had decay channels. The exclusion limits are shown for the production cross section of a generic neutral Higgs boson, phi, as a function of the Higgs boson mass and for h/H/A production in the MSSM as a function of the parameters m_A and tan(beta) in the m_h-max scenario.