Search for the Standard Model Higgs boson in H-> tau tau decays in proton-proton collisions with the ATLAS detector

A search for the Standard Model (SM) Higgs boson decaying into a pair of $\tau$ leptons is reported. The analysis, exploiting each of the $\tlep\tlep$, $\tlep\thad$ and $\thad\thad$ final states, is based on data samples of proton-proton collisions collected by the ATLAS experiment at the LHC and corresponding to integrated luminosities of $4.6\,\ifb$ and $13.0\,\ifb$ at centre-of-mass energies of ${\sqrt{s}=7 }$ \TeV{} and $8\,$\TeV{}, respectively. The observed (expected) upper limit at 95$\%$ CL on the cross-section times the branching ratio for SM $H \to \tau^+\tau^-$ is found to be 1.9 (1.2) times the SM prediction for a Higgs boson with mass $m_{H}$=125~GeV. For this mass, the observed (expected) deviation from the background-only hypothesis corresponds to a local significance of 1.1 (1.7) standard deviations.