Measurement of the Top Quark Pair Production Cross Section in $\mathit{p}\overline{\mathit{p}}$ Collisions

We present a measurement of the $t\overline{t}$ production cross section in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$ by the D0 experiment at the Fermilab Tevatron. The measurement is based on data from an integrated luminosity of approximately $125{\mathrm{pb}}^{-1\mathrm{}}$ accumulated during the 1992–1996 collider run. We observe 39 $t\overline{t}$ candidate events in the dilepton and $\mathrm{lepton}+\mathrm{jets}$ decay channels with an expected background of $13.7\pm 2.2$ events. For a top quark mass of $173.3\mathrm{GeV}{/c}^2$, we measure the $t\overline{t}$ production cross section to be $5.5\pm 1.8\mathrm{pb}$.