Search for direct top squark pair production in final states with two tau leptons in pp collisions at (Formula presented.) TeV with the ATLAS detector

© 2016, CERN for the benefit of the ATLAS collaboration.A search for direct pair productionof the supersymmetric partner of the top quark, decaying via a scalar tau to a nearly massless gravitino, has been performed using 20 fb (Formula presented.) of proton–proton collision data at (Formula presented.). The data were collected by the ATLAS experimentat the LHC in 2012. Topsquark candidates are searched for in events with either two hadronically decaying tau leptons, one hadronically decaying tau and one light lepton, or two light leptons. No significant excess over the Standard Model expectation is found. Exclusion limits at (Formula presented.) confidence level are set as a function of the topsquark and scalar tau masses. Depending on the scalar tau mass, ranging from the (Formula presented.) LEP limit to the topsquark mass, lower limits between 490 and (Formula presented.) are placed on the topsquark mass within the model considered.