Measurement of thett¯production cross section inpp¯collisions using dilepton events

We present a measurement of the $t\overline{t}$ pair production cross section in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$ utilizing approximately $425\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of data collected with the D0 detector. We consider decay channels containing two high ${p}_{T}$ charged leptons (either $e$ or $\ensuremath{\mu}$) from leptonic decays of both top-daughter $W$ bosons. These were gathered using four sets of selection criteria, three of which required that a pair of fully identified leptons (i.e., $e\ensuremath{\mu}$, $ee$, or $\ensuremath{\mu}\ensuremath{\mu}$) be found. The fourth approach imposed less restrictive criteria on one of the lepton candidates and required that at least one hadronic jet in each event be tagged as containing a $b$ quark. For a top quark mass of 175 GeV, the measured cross section is $7.4\ifmmode\pm\else\textpm\fi{}1.4(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}1.0(\mathrm{syst})\text{ }\text{ }\mathrm{pb}$ and for the current Tevatron average top quark mass of 170.9 GeV, the resulting value of the cross section is $7.8\ifmmode\pm\else\textpm\fi{}1.8(\mathrm{stat}+\mathrm{syst})\text{ }\text{ }\mathrm{pb}$.