Measurement of semileptonic branching fractions of B mesons to narrow D** states.
Phys Rev Lett 95:17 (2005) 171803
Abstract:
Using the data accumulated in 2002-2004 with the D0 detector in proton-antiproton collisions at the Fermilab Tevatron collider with a center-of-mass energy of 1.96 TeV, the branching fractions of the decays B --> D0(1)(2420)mu+ vmuX and B --> D2(*0)(2460)mu+ vmuX and their ratio have been measured: B(b --> B) x B(B --> D0(1)mu+ vmuX) x B(D0(*0) --> D*- pi+) = [0.087 +/- 0.007(stat) +/- 0.014(syst)]%; B(b --> B) x B(B --> D2(*0) mu+ vmuX) x B(D2(*0) --> D*- pi+) = [0.035 +/- 0.007(stat) +/- 0.008(syst)]% and [B(B --> D2(*0)mu+ vmuX) x B(D2(*0) --> D*- pi+)]/[B(B --> D0(1)mu+ vmuX) x B(D0(1) --> D*- pi+)] = 0.39 +/- 0.09(stat) +/- 0.12 (syst), where the charge conjugated states are always implied.Measurement of the lifetime difference in the Bs0 system
Physical Review Letters 95:17 (2005)
Abstract:
We present a study of the decay Bs0â†'J/ÏÏ•. We obtain the CP-odd fraction in the final state at time zero, R⚥=0.16±0.10(stat)±0.02(syst), the average lifetime of the (Bs0, BÂs0) system, Ï.,Â(Bs0)=1.39- 0.16+0.13(stat)-0.02+0.01(syst)ps, and the relative width difference between the heavy and light mass eigenstates, Î"Î"/ Î"Â≡(Î"L-Î"H)/ Î"Â=0.24-0.38+0.28(stat)-0.04+0.03(syst). With the additional constraint from the world average of the Bs0 lifetime measurements using semileptonic decays, we find Ï.,Â(Bs0)=1.39±0.06ps and Î"Î"/Î"Â=0.25-0.15+0.14. For the ratio of the Bs0 and B0 lifetimes we obtain Ï.,Â(Bs0)Ï.,(B0)=0. 91±0.09(stat)±0.003(syst). © 2005 The American Physical Society.Measurement of the lifetime difference in the B0(s) system.
Phys Rev Lett 95:17 (2005) 171801
Abstract:
We present a study of the decay B0(s) --> J/psiphi. We obtain the CP-odd fraction in the final state at time zero, Rperpendicular = 0.16 +/- 0.10(stat) +/- 0.02 (syst), the average lifetime of the (B0(s), B0(s)) system, tau(B0(s)) = 1.39(+0.13)(-0.16)(stat)(+0.01)(-0.02)(syst) ps, and the relative width difference between the heavy and light mass eigenstates, DeltaGamma/Gamma tripple bond (GammaL - GammaH)/Gamma = 0.24(+0.28)(-0.38)(stat)(+0.03)(-0.04)(syst). With the additional constraint from the world average of the lifetime measurements using semileptonic decays, we find tau(B0(s)) = 1.39 +/- 0.06 ps and DeltaGamma/Gamma = 0.25(+0.14)(-0.15). For the ratio of the B0(s) and B0 lifetimes we obtain tau(B0(s))/tau(B0) = 0.91 +/- 0.09(stat) +/- 0.003(syst).Measurement of the tt̄ production cross section in pp̄ collisions at √s = 1.96 TeV using kinematic characteristics of lepton + jets events
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 626:1-4 (2005) 45-54
Abstract:
We present a measurement of the top quark pair (tt̄) production cross section (σtt̄) in pp̄ collisions at a center-of-mass energy of 1.96 TeV using 230 pb-1 of data collected by the DØ detector at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), large missing transverse energy, and at least four jets, and extract the tt̄ content of the sample based on the kinematic characteristics of the events. For a top quark mass of 175 GeV, we measure σtt̄=6.7-1.3+1.4(stat) -1.1+1.6(syst)±0.4(lumi) pb, in good agreement with the standard model prediction. © 2005 Elsevier B.V. All rights reserved.Measurement of the tt̄ production cross section in pp̄ collisions at √s = 1.96 TeV in dilepton final states
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 626:1-4 (2005) 55-64