Observability of Same-Charge Lepton Topologies in Fully Leptonic Top Quark Pair Events in CMS

At the Large Hadron Collider di-leptonic ttbar+jets events can be selected with a relatively high signal-to-noise ratio and efficiency, with background events produced via Standard Model diagrams. Within the clean sample of these events, both isolated leptons have an opposite electric charge. In several models beyond the Standard Model tt/tbartbar+jets topologies are predicted, kinematically similar to the Standard Model ttbar+jets signature, where both leptons have an equal electric charge. Such a signal of new physics can be diluted by the mis-identification of the leptons or their electric charge in Standard Model ttbar+jets events. The observability of an excess of same-charge di-lepton signals above the mis-reconstruction of the Standard Model background is presented, assuming the same topology. With an integrated luminosity of 30/fb, a same-charge di-lepton signature of pp->tt/tbartbar events with a cross section larger than 1.2pb is visible in the measurement of the ratio between same-charge and opposite-charge lepton pair events.