Search for a Heavy Top-Like Quark in p\bar{p} Collisions at {\surd}s =   1.96 TeV
  We present the results of a search for pair production of a heavy top-like (t') quark decaying to Wq final states using data corresponding to an integrated luminosity of 5.6 fb-1 collected by the CDF II detector in pp collisions at {\surd}s = 1.96 TeV. We perform parallel searches for t' \to Wb and t' \to 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 \bar{t} production cross section and exclude a standard model fourth-generation t' quark decaying to W b (W q) with mass below 358 (340) GeV/c2 at 95% CL. 
CDF Collaboration: T. Aaltonen, B. \'Alvarez Gonz\'alezv, S. Amerio,   D. Amidei, A. Anastassov, A. Annovi, J. Antos, G. Apo...
hep-ex