Search for supersymmetry in events with leptons (e, µ, t), jets and missing transverse energy with the ATLAS detector at the LHC

Two searches for events containing t-leptons, jets, large missing transverse momentum, and zero or one light leptons (l = e,µ) in the final state have been performed using proton-proton collision data at vs = 7 TeV, recorded with the ATLAS detector at the Large Hadron Collider. The first search was performed using 2:05fb-1 of the ATLAS data collected in 2011, and focused on the final state containing two hadronically decaying t-leptons. For the second search the dataset was extended to 4:7fb-1, and four separate channels (1t, 2t, t+e, t+µ) were combined for the final result. No excess above the Standard Model background expectation is observed and 95% CL visible cross-section upper limits for new phenomena are set. In the framework of gauge-mediated SUSY-breaking models (GMSB), exclusion limits on the GMSB mass scale ? are set at 54 TeV in the regions where the lightest ~t is the next-to-lightest SUSY particle (tan ß > 20). These limits provide the most stringent tests to date of GMSB models in a large part of the considered parameter space.