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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the Lambda(0)(b) Lifetime in Lambda(0)(b) -> Lambda(+)(c)pi(-) Decays in p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 104(10), 102002–8pp.
Abstract: We report a measurement of the lifetime of the Lambda(0)(b) baryon in decays to the Lambda(+)(c)pi(-) final state in a sample corresponding to 1.1 fb(-1) collected in p (p) over bar collisions at root s = 1.96 TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed Lambda(0)(b) events we measure tau(Lambda(0)(b) ) = 1.401 +/- 0.046(stat) +/- 0.035(syst) ps (corresponding to c tau(Lambda(0)(b)) = 420.1 +/- 13.7(stat) +/- 10.6(syst) μm, where c is the speed of light). The ratio of this result and the world average B-0 lifetime yields tau(Lambda(0)(b))/tau(B-0) = 0.918 +/- 0.038 (stat) and (syst), in good agreement with recent theoretical predictions.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the WW plus WZ Production Cross Section Using the lepton plus jets Final State at CDF II. Phys. Rev. Lett., 104(10), 101801–8pp.
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 p (p) over bar collision data at root 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 5.4 sigma 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.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for New Bottomlike Quark Pair Decays Q(Q)over-bar -> (tW +/-)((t)over-barW +/- in Same-Charge Dileption Events. Phys. Rev. Lett., 104(9), 091801–8pp.
Abstract: We report the most restrictive direct limits on masses of fourth- generation down- type quarks b0, and quarklike composite fermions (B or T5= 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 mb0, mB > 338 GeV= c2 and mT5= 3 > 365 GeV= c2 at 95% confidence level.
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CDF Collaboration(Aaltonen, T. et al), Cabrera, S., & Cuenca Almenar, C. (2010). Measurements of the top-quark mass using charged particle tracking. Phys. Rev. D, 81(3), 032002–21pp.
Abstract: We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb(-1) of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9(-8.5)(+9.5)(stat) +/- 2.9(syst) GeV/c(2), and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5(-8.9)(+8.8)(stat) +/- 3.8(syst) GeV/c(2). These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 +/- 6.3(stat) +/- 2.6(syst) GeV/c(2) .
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurements of branching fraction ratios and CP asymmetries in B-+/- -> DCPK +/- decays in hadron collisions. Phys. Rev. D, 81(3), 031105–9pp.
Abstract: We reconstruct B-+/- -> DK +/- decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1 fb(-1) of integrated luminosity. We select decay modes where the D meson decays to either K-pi(+) (flavor eigenstate) or K-K+, pi(-)pi(+) (CP-even eigenstates), and measure the direct CP asymmetry A(CP+) = 0.39 +/- 0.17(stat) +/- 0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions RCP+ = 1.30 +/- 0.24(stat) +/- 0.12(syst). These measurements will improve the determination of the Cabibbo-Kobayashi-Maskawa angle gamma. They are performed here for the first time using data from hadron collisions.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the top quark mass in the dilepton channel using m(T2) at CDF. Phys. Rev. D, 81(3), 031102–9pp.
Abstract: We present measurements of the top quark mass using m(T2), a variable related to the transverse mass in events with two missing particles. We use the template method applied to t (t) over bar dilepton events produced in p (p) over bar collisions at Fermilab's Tevatron Collider and collected by the CDF detector. From a data sample corresponding to an integrated luminosity of 3.4 fb(-1), we select 236 t (t) over bar candidate events. Using the m(T2) distribution, we measure the top quark mass to be M-top = 168.0(-4.0)(4.8)(stat) +/- 2.9(syst) GeV/c(2). By combining m(T2) with the reconstructed top quark mass distributions based on a neutrino weighting method, we measure M-top = 169.3 +/- 2.7(stat) +/- 3.2(syst) GeV/c(2). This is the first application of the m(T2) variable in a mass measurement at a hadron collider.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Inclusive Search for Standard Model Higgs Boson Production in the WW Decay Channel Using the CDF II Detector. Phys. Rev. Lett., 104(6), 061803–8pp.
Abstract: We present a search for standard model (SM) Higgs boson production using p (p) over bar collision data at root s = 1. 96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4. 8 fb(-1). We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (sigma(H)) for values of the Higgs boson mass (m(H)) in the range from 110 to 200 GeV. These limits are the most stringent for m(H) > 130 GeV and are 1.29 above the predicted value of sigma(H) for m(H) 165 GeV.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Combination of Tevatron Searches for the Standard Model Higgs Boson in the W+W- Decay Mode. Phys. Rev. Lett., 104(6), 061802–11pp.
Abstract: We combine searches by the CDF and D0 Collaborations for a Higgs boson decaying to W+W-. The data correspond to an integrated total luminosity of 4.8 (CDF) and 5.4 (D0) fb(-1) of p (p) over bar collisions at root s = 1.96 TeV at the Fermilab Tevatron collider. No excess is observed above background expectation, and resulting limits on Higgs boson production exclude a standard model Higgs boson in the mass range 162-166 GeV at the 95% C.L.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for Supersymmetry with Gauge-Mediated Breaking in Diphoton Events with Missing Transverse Energy at CDF II. Phys. Rev. Lett., 104(1), 011801–8pp.
Abstract: We present the results of a search for supersymmetry with gauge-mediated breaking and (chi) over tilde (1)(0) -> gamma(G) over tilde in the gamma gamma + missing transverse energy final state. In 2.6 +/- 0.2 fb(-1) of p (p) over bar collisions at root s 1.96 TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4 +/- 0.4 events. We set limits on the cross section at the 95% C.L. and place the world's best limit of 149 GeV/c(2) on the (chi) over tilde (1)(0) mass at tau((chi) over tilde 01) << 1 ns. We also exclude regions in the (chi) over tilde (1)(0) mass-lifetime plane for tau((chi) over tilde 01) less than or similar to 2 ns.
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