We have studied tbar-t production using multijet final states in pbar-p collisions at a center-of-mass energy of 1.8 TeV, with an integrated luminosity of 110.3 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 tbar-t production cross section, and yields a cross section of 7.1 +/- 2.8(stat.) +/- 1.5(syst.) pb, assuming a top quark mass of 172.1 GeV/c^(2). Combining this result with previous D0 measurements, where one or both of the W bosons decay leptonically, gives a tbar t production cross section of 5.9 +/- 1.2(stat) +/- 1.1(syst) pb.
The second value is the combination of the data reported here combined withthe previous result of D0 reported in PRL 79(1997)1203.
We present an analysis of dilepton events originating from top-antitop production in proton-antiproton collisions at sqrt{s}=1.8 TeV at the Fermilab Tevatron Collider. The sample corresponds to an integrated luminosity of 109+-7 pb^{-1}. We observe 9 candidate events, with an estimated background of 2.4+-0.5 events. We determine the mass of the top quark to be M_top = 161+-17(stat.)+-10(syst.) GeV/c^2. In addition we measure a top-antitop production cross section of 8.2+4.4-3.4 pb (where M_top = 175 GeV/c^2 has been assumed for the acceptance estimate).
No description provided.
We present a measurement of the ttbar production cross section in ppbar collisions at root(s) = 1.8TeV by the D0 experiment at the Fermilab Tevatron. The measurement is based on data from an integrated luminosity of approximately 125 pb~-1 accumulated during the 1992-1996 collider run. We observe 39 ttbar candidate events in the dilepton and lepton+jets decay channels with an expected background of 13.7+-2.2 events. For a top quark mass of 173.3GeV/c~2, we measure the ttbar production cross section to be 5.5+-1.8 pb.
Different channels are used for evaluation of the cross section magnitudes. The last value is obtained from the previous one by adding the errors in quadrature.
We present evidence for dilepton events from t tbar production with one electron or muon and one hadronically decaying tau lepton from the decay t tbar -> (l nu_l) (tau nu_tau) b bbar, (l=e, mu), using the Collider Detector at Fermilab (CDF). In a 109 pb~-1 data sample of p pbar collisions at sqrt(s) = 1.8 TeV we expect 1 signal event and a total background of 2 events; we observe 4 candidate events (2 e tau and 2 mu tau). Three of these events have jets identified as b candidates, compared to an estimated background of 0.28+-0.02 events.
Two complementary techniques for identifying TAU's are used (see text), one'track-based' (C=TRCK) and other 'calorimeter-based' (C=CALO).
Forum