Search for a Heavy Top-Like Quark in p\bar{p} Collisions at {\surd}s = 1.96 TeV

TL;DR

This paper reports a search for a hypothetical heavy top-like quark (t') in proton-antiproton collisions at 1.96 TeV, setting mass exclusion limits based on data from the CDF II detector.

Contribution

It introduces a new search method for heavy t' quarks decaying to Wq final states using a two-dimensional fit of energy and mass distributions.

Findings

Excluded t' quark masses below 358 GeV/c2 for Wb decay

Excluded t' quark masses below 340 GeV/c2 for Wq decay

Set upper limits on t' pair production cross section

Abstract

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.