Search for resonant production of t¯t pairs in 4.8 fb−1 of integrated luminosity of p¯p collisions at √s=1.96 TeV

Abstract

We search for resonant production of t¯t pairs in 4.8 fb−1 integrated luminosity of p¯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 of the t¯t candidate invariant mass is sampled. These probability density functions are used to construct a likelihood function, whereby the cross section for resonant t¯t production is estimated, given a hypothetical resonance mass and width. The data indicate no evidence of resonant production of t¯t pairs. A benchmark model of leptophobic Z′→t¯t is excluded with mZ′<900 GeV/c2 at 95% confidence level.