We search for resonant production of $t\overline{t}$ pairs in $4.8{\mathrm{fb}}^{-1}$ integrated luminosity of $p\overline{p}$ collision data at $\sqrt{s}=1.96\mathrm{TeV}$ in the $\mathrm{\text{lepton}}+\mathrm{\text{jets}}$ 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 $t\overline{t}$ candidate invariant mass is sampled. These probability density functions are used to construct a likelihood function, whereby the cross section for resonant $t\overline{t}$ production is estimated, given a hypothetical resonance mass and width. The data indicate no evidence of resonant production of $t\overline{t}$ pairs. A benchmark model of leptophobic $Z^{\prime }\to t\overline{t}$ is excluded with $m_{Z^{\prime }}<900\mathrm{GeV}/{\mathrm{c}}^2$ at 95% confidence level.

• Received 25 July 2011

DOI:https://doi.org/10.1103/PhysRevD.84.072004