Trileptons from the top quark

The cascade decays of tt-bar, tb-bar, bt-bar, and bb-bar systems produced in pp-bar collisions by strong or electroweak mechanisms lead to trilepton events, which offer top-quark signatures free from cc-bar and Drell-Yan backgrounds. Even a few events could be valuable. Since at least two of the leptons must have a common parent, same-sign trileptons or events with opposite-sign pair masses greater than m/sub b/ must have top origins, and the minimum pair invariant mass in such events gives a lower bound on the top mass. Alternative tt-bar and tb-bar (bt-bar ) origins can be distinguished by topology and/or lepton isolation