| Resumen |
We present the first simultaneous measurement of the ratio of branching fractions, R=B(t→Wb)/B(t→Wq), with q being a d, s, or b quark, and the top-quark pair production cross section σtt̄ in the lepton plus jets channel using 0.9fb-1 of pp̄ collision data at √s=1.96TeV collected with the D0 detector. We extract R and σtt̄ by analyzing samples of events with 0, 1, and 2 identified b jets. We measure R=0.97-0.08+0.09(stat+syst) and σtt̄=8.18-0.84+0.90(stat+syst)±0.50(lumi)pb, in agreement with the standard model prediction. |
