Measurement of absolute branching fractions of inclusive semileptonic decays of charm and charmed-strange mesons
Physical Review D Particles Fields Gravitation and Cosmology 81:5 (2010)
Abstract:
We have measured the inclusive semileptonic branching fractions of D0, D+, and Ds+ mesons. For these measurements, we have used the full CLEO-c open-charm data samples, 818pb-1 at ECM=3.774GeV, giving D0D̄0 and D+D- events, and 602pb -1 at ECM=4.170GeV, giving Ds*±Ds" events. We obtain B(D0→Xe+νe)=(6.46±0.09±0.11)%, B(D +→Xe+νe)=(16.13±0.10±0.29)%, and B(Ds+→Xe+νe)=(6.52±0.39±0.15)%, where the first uncertainties are statistical and the second are systematic. From these and lifetimes obtained elsewhere, we obtain the ratios of semileptonic decay widths Γ(D+→Xe+νe)/Γ(D0→Xe +νe)=0.985±0.015±0.024 and Γ(Ds+→Xe +νe)/Γ(D0→Xe+νe)=0.828±0. 051±0.025. The ratio of D+ and D0 is consistent with the isospin symmetry prediction of unity, and the ratio of Ds+ and D0 differs from unity, as expected. © 2010 The American Physical Society.Study of the associated production of photons and b-quark jets in pp̄ collisions at √s=1.96TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 81:5 (2010)
Abstract:
The cross section for photon production in association with at least one jet containing a b quark has been measured in proton antiproton collisions at √s=1.96TeV. The data sample used corresponds to an integrated luminosity of 340pb-1 collected with the CDF II detector. Both the differential cross section as a function of photon transverse energy ETγ and the total cross section are measured and compared to a next-to-leading order prediction for the process. © 2010 The American Physical Society.Measurement of the Lambdab0 lifetime in Lambdab0 --> Lambdac+pi- decays in pp collisions at square root of s = 1.96 TeV.
Phys Rev Lett 104:10 (2010) 102002
Abstract:
We report a measurement of the lifetime of the Lambda(b)(0) baryon in decays to the Lambda(c)(+)pi(-) final state in a sample corresponding to 1.1 fb(-1) collected in pp collisions at square root of s = 1.96 TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed Lambda(b)(0) events we measure tau(Lambda(b)(0)) = 1.401 +/- 0.046(stat) +/- 0.035(syst) ps (corresponding to ctau(Lambda(b)(0)) = 420.1 +/- 13.7(stat) +/- 10.6(syst) microm, where c is the speed of light). The ratio of this result and the world average B(0) lifetime yields tau(Lambda(b)(0))/tau(B(0)) = 0.918 +/- 0.038 (stat) and (syst), in good agreement with recent theoretical predictions.Measurement of the WW + WZ production cross section using the lepton + jets final state at CDF II.
Phys Rev Lett 104:10 (2010) 101801
Abstract:
We report two complementary measurements of the WW + WZ cross section in the final state consisting of an electron or muon, missing transverse energy, and jets, performed using pp collision data at square root of s = 1.96 TeV collected by the CDF II detector. The first method uses the dijet invariant mass distribution while the second more sensitive method uses matrix-element calculations. The result from the second method has a signal significance of 5.4sigma and is the first observation of WW + WZ production using this signature. Combining the results gives sigma(WW + WZ) = 16.0 +/- 3.3 pb, in agreement with the standard model prediction.Measurement of the Λb0 lifetime in Λb0→Λc+π - decays in pp̄ collisions at √s=1.96TeV
Physical Review Letters 104:10 (2010)