A search for resonant production of t(bar t) pairs in 4.8 fb-1 of integrated luminosity of p(bar p) collisions at √s = 1.96 TeV

We search for resonant production of t(bar t) pairs in 4.8 fb-1 integrated luminosity of p(bar p) collision data at √s = 1.96 TeV in the lepton+jets decay channel, where one top quark decays leptonically and the other hadronically. A matrix element reconstruction technique is used; for each event a probability density function (pdf) of the t(bar t) candidate invariant mass is sampled. These pdfs are used to construct a likelihood function, whereby the cross section for resonant t(bar t) production is estimated, given a hypothetical resonance mass and width. The data indicate no evidence of resonant production of t(bar t) pairs. A benchmark model of leptophobic Z' → t(bar t) is excluded with mZ' < 900 GeV at 95% confidence level.