Measurement of the top quark pair production cross section inpp¯collisions using multijet final states

We have studied $t\overline{t}$ production using multijet final states in $p\overline{p}$ collisions at a center-of-mass energy of 1.8 TeV, with an integrated luminosity of 110.3 ${\mathrm{pb}}^{-1}.$ Each of the top quarks with these final states decays exclusively to a bottom quark and a W boson, with the W bosons decaying into quark-antiquark pairs. The analysis has been optimized using neural networks to achieve the smallest expected fractional uncertainty on the $t\overline{t}$ production cross section, and yields a cross section of 7.1$\pm$2.8 (stat)$\pm$1.5 (syst) pb, assuming a top quark mass of 172.1 GeV/$c^2.$ Combining this result with previous DØ measurements, where one or both of the W bosons decay leptonically, gives a $t\overline{t}$ production cross section of $5.9\pm 1.2\hspace{0.5em}\left(\mathrm{stat}\right)\pm 1.1\hspace{0.5em}\left(\mathrm{syst}\right)\mathrm{}\mathrm{pb}.$