Measurement of the Lambdab0 lifetime in Lambdab0 --> Lambdac+pi- decays in pp collisions at square root of s = 1.96 TeV.
Physical review letters 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.
Physical review letters 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.Search for new bottomlike quark pair decays QQ-->(tW(+)(-))(tW(+)(-)in same-charge dilepton events.
Physical review letters 104:9 (2010) 091801
Abstract:
We report the most restrictive direct limits on masses of fourth-generation down-type quarks b{'}, and quarklike composite fermions (B or T{5/3}), decaying promptly to tW{-/+}. We search for a significant excess of events with two same-charge leptons (e, mu), several hadronic jets, and missing transverse energy. An analysis of data from pp collisions with an integrated luminosity of 2.7 fb{-1} collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits m{b{'}}, m{B}>338 GeV/c{2} and m{T{5/3}}>365 GeV/c{2} at 95% confidence level.Search for technicolor particles produced in association with a W Boson at CDF.
Physical review letters 104:11 (2010) 111802
Abstract:
We present a search for the technicolor particles rho{T} and pi_{T} in the process pp-->rho{T}-->Wpi{T} at a center of mass energy of sqrt[s]=1.96 TeV. The search uses a data sample corresponding to approximately 1.9 fb{-1} of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is W-->lnu and pi{T}-->bb, bc or bu depending on the pi{T} charge. We select events with a single high-p{T} electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple b-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the rho{T}-pi{T} mass plane. As a result, a large fraction of the region m(rho{T})=180-250 GeV/c{2} and m(pi{T})=95-145 GeV/c{2} is excluded.Measurements of branching fraction ratios and CP asymmetries in B ±→DCPK± decays in hadron collisions
Physical Review D - Particles, Fields, Gravitation and Cosmology 81:3 (2010)