Physics studies of processes with t leptons in the final state, while challenging at hadron colliders, are of great importance at the LHC. The τ leptons provide important signatures in searches for the Higgs boson as well ......

In this thesis, a search for the H → bb decay of the Standard Model Higgs boson is presented. A dataset of 20.2 fb^-1 recorded by the ATLAS detector at CERN is ......