Xiaoxiao Wang

The Higgs discovery at the LHC has brought new attention to the hierarchy problem and the theory of Supersymmetry (SUSY). The supersymmetric partner of the top quark - the top squark (stop), is of paramount importance as it contributes the largest higher-order radiative corrections to the Higgs squared-mass. Naturalness arguments favor a light stop, making it a good candidate for discovery at the LHC. A search of the stop pair production in final states with one isolated lepton, jets, and missing transverse momentum will be presented. The search is performed with proton-proton collision data at \sqrt{s}=8 TeV collected by the ATLAS detector at the LHC in 2012, corresponding to an integrated luminosity of 20 fb^{-1}. The stop decay mode studied is mainly that to a top quark and a lightest neutralino, which is assumed to be the lightest supersymmetric particle (LSP) and evades detection. A technique that reconstructs the decays of the boosted top quark is used to increase the sensitivity at high stop masses. Similar techniques will be crucial for LHC Run2 searches where regimes of higher masses are probed. Results of other stop decays will also be reported, including a mixed decay where the stop can in addition decay into a bottom quark and the lightest chargino.