Search for a Heavy Toplike Quark in p p ¯ Collisions at √ s = 1.96 TeV

Abstract

We present the results of a search for pair production of a heavy toplike (t ′) quark decaying to Wq final states using data corresponding to an integrated luminosity of 5.6fb -1 collected by the CDF II detector in pp̄ collisions at √s=1.96TeV. We perform parallel searches for t ′→Wb and t ′→Wq (where q is a generic down-type quark) in events containing a lepton and four or more jets. By performing a fit to the two-dimensional distribution of total transverse energy versus reconstructed t ′ quark mass, we set upper limits on the t ′t ̄′ production cross section and exclude a standard model fourth-generation t ′ quark decaying to Wb (Wq) with mass below 358 (340)GeV/c2 at 95% C.L. © 2011 American Physical Society.