$t\overline{t}$ production cross section in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$

Results are presented on a measurement of the $t\overline{t}$ pair production cross section in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$ from nine independent decay channels. The data were collected by the DØ experiment during the 1992–1996 run of the Fermilab Tevatron Collider. A total of 80 candidate events is observed with an expected background of $38.8\pm 3.3$ events. For a top quark mass of $172.1\mathrm{GeV}{/c}^2,$ the measured cross section is $5.69\pm 1.21\left(\mathrm{stat}\right)\pm 1.04\left(\mathrm{syst}\right)\mathrm{pb}.$