UC Santa Cruz

We present a search for new exotic physics in pp collisions at √s = 8 TeV recorded by the ATLAS detector at the Large Hadron Collider (LHC) at CERN. Our search is focusing on the production of four top-quark final states. Specifically, we are looking for events with two or more top-quarks produced with very high transverse momentum, tagged using jet substructure variables. Events with at least two top-tagged jets are also required to have at least two b-tagged jets, with a further requirement that one of the b-tagged jets lie outside the conical radius of the top-tagged jets. Finally, we look in events that have a large amount of total transverse momentum (HT) that is optimized for several potential new signal models (low HT and high HT). In a data sample of 20.3 fb^-1 we measured an expected background of 13.04 ± 3.150^+3.925_-4.751 events in the low-HT channel and measured an expected background of 5.024 ± 1.918^+1.753_{-2.971 events in the high-HT channel. We expect to set a limit on the Kaluza-Klein mass scale mKK > 1.06 TeV at the 95% CL assuming no excess of or deficit of events are seen in the data.}