A Search for ttbar Resonances in the Dilepton Channel in 1.04 fb^-1 of pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

Abstract: A search for a high mass ttbar resonance in pp collisions at sqrt(s) = 7 TeV at the LHC is presented. We search for such a resonance using the final state where the $W$ bosons from the top quark decay into either an electron or a muon (dilepton final state). The data were recorded by the ATLAS experiment during 2011 and correspond to a total integrated luminosity of L = 1.04 fb^-1. No statistically significant excess above the Standard Model expectation is observed. Upper limits at the 95% Confidence Level (C.L.) are set on the cross section times branching ratio of the resonance decaying to ttbar pairs as a function of the resonance mass. A lower mass limit of 0.84 TeV is set for the case of a Kaluza-Klein gluon resonance in the Randall-Sundrum Model.