Search for a Higgs boson in the ditau decay with ATLAS

Following the discovery of a Higgs-like particle with a mass around 125 GeV in the diphoton, ZZ and WW decay modes, it is important to search for a Higgs boson decaying into fermion pairs such as $\tau\tau$ and $b\bar{b}$. These decays are also very important in the MSSM scenario. The observation or non-observation of these decay modes could have important implications on SM physics and new physics. I will report recent SM $H\to\tau\tau$ search result in the $ll$, $lh$ and $hh$ channels using pp collision data collected by ATLAS at $\sqrt{s}=7$ TeV and $\sqrt{s}=8$ TeV. I will focus on background estimations, event categorization strategy and multivariate techniques. Interpretations of the final observed data events and SM predictions will be presented.