Measurement of the tt̄ production cross section in pp̄ collisions using dilepton events

We present a measurement of the tt pair production cross section in pp collisions at {radical}(s)=1.96 TeV utilizing approximately 425 pb{sup -1} of data collected with the D0 detector. We consider decay channels containing two high p{sub T} charged leptons (either e or {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{mu}, ee, or {mu}{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{+-}1.4(stat){+-}1.0(syst) pb and for the current Tevatron average top quark mass of 170.9 GeV, the resulting value of the cross section is 7.8{+-}1.8(stat+syst) pb.