Exclusion of exotic top-like quarks with -4/3 electric charge using jet-charge tagging in single-lepton tt¯ events at CDF

Abstract

We report on a measurement of the top-quark electric charge in tt events in which one W boson originating from the top-quark pair decays into leptons and the other into hadrons. The event sample was collected by the CDF II detector in ffiffi s p ¼ 1:96 TeV proton-antiproton collisions and corresponds to 5:6 fb 1. We find the data to be consistent with the standard model and exclude the existence of an exotic quark with 4=3 electric charge and mass of the conventional top quark at the 99% confidence level.