211 research outputs found

    Search for rare quark-annihilation decays, B --> Ds(*) Phi

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    We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications

    Evaporative evolution of a Na–Cl–NO(3)–K–Ca–SO(4)–Mg–Si brine at 95°C: Experiments and modeling relevant to Yucca Mountain, Nevada

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    A synthetic Topopah Spring Tuff water representative of one type of pore water at Yucca Mountain, NV was evaporated at 95°C in a series of experiments to determine the geochemical controls for brines that may form on, and possibly impact upon the long-term integrity of waste containers and drip shields at the designated high-level, nuclear-waste repository. Solution chemistry, condensed vapor chemistry, and precipitate mineralogy were used to identify important chemical divides and to validate geochemical calculations of evaporating water chemistry using a high temperature Pitzer thermodynamic database. The water evolved toward a complex "sulfate type" brine that contained about 45 mol % Na, 40 mol % Cl, 9 mol % NO(3), 5 mol % K, and less than 1 mol % each of SO(4), Ca, Mg, ∑CO(2)(aq), F, and Si. All measured ions in the condensed vapor phase were below detection limits. The mineral precipitates identified were halite, anhydrite, bassanite, niter, and nitratine. Trends in the solution composition and identification of CaSO(4 )solids suggest that fluorite, carbonate, sulfate, and magnesium-silicate precipitation control the aqueous solution composition of sulfate type waters by removing fluoride, calcium, and magnesium during the early stages of evaporation. In most cases, the high temperature Pitzer database, used by EQ3/6 geochemical code, sufficiently predicts water composition and mineral precipitation during evaporation. Predicted solution compositions are generally within a factor of 2 of the experimental values. The model predicts that sepiolite, bassanite, amorphous silica, calcite, halite, and brucite are the solubility controlling mineral phases

    Observation of CP violation in B ->eta/K-0 decays

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    We present measurements of the time-dependent CP-violation parameters S and C in B-0 -> eta K-'(0) decays. The data sample corresponds to 384 x 10(6) B (B) over bar pairs produced by e(+)e(-) annihilation at the Upsilon(4S). The results are S = 0.58 +/- 0.10 +/- 0.03 and C = -0.16 +/- 0.07 +/- 0.03. We observe mixing-induced CP violation with a significance of 5.5 standard deviations in this b -> s penguin dominated mode

    Measurement of branching fractions and resonance contributions for B-0 ->(D)over-bar(0)K(+)pi(-) and search for B-0 ->(DK+)-K-0 pi(-) decays

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    Using 226x10(6) Upsilon(4S)-> B (B) over bar events collected with the BABAR detector at the PEP-II e(+)e(-) storage ring at the Stanford Linear Accelerator Center, we measure the branching fraction for B-0->(D) over bar (0)K(+)pi(-), excluding B-0-> D*-K+, to be B(B-0->(0)K(+)pi(-))=(88 +/- 15 +/- 9)x10(-6). We observe B-0->(D) over bar K-0(*)(892)(0) and B-0-> D-2(*)(2460)K--(+) contributions. The ratio of branching fractions B(B-0-> D*-K+)/B(B-0-> D(*-)pi(+))=(7.76 +/- 0.34 +/- 0.29)% is measured separately. The branching fraction for the suppressed mode B-0-> D(0)K(+)pi(-) is B(B-0-> D(0)K(+)pi(-))< 19x10(-6) at the 90% confidence level

    Determinations of vertical bar V-ub vertical bar from inclusive semileptonic B decays with reduced model dependence

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    We report two novel determinations of vertical bar V-ub vertical bar with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from Y(4S) -> B (B) over bar events. In one approach, we combine the inclusive (B) over bar -> X(u)l (v) over bar rate, integrated up to a maximum hadronic mass m(X) X-s gamma photon energy spectrum. We obtain vertical bar V-ub vertical bar = (4.43 +/- 0.38(stat) +/- 0.25(syst) +/- 0.29(theo)) x 10(-3). In another approach we measure the total (B) over bar -> X(u)l (v) over bar rate over the full phase space and find vertical bar V-ub vertical bar = 3.84 +/- 0.70(stat) +/- 0.30(syst) +/- 0.10(theo)) x 10(-3)

    Dalitz plot analysis of the decay B±→K±K±K∓

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    We analyze the three-body charmless decay B-+/-->(KKK -/+)-K-+/--K-+/- using a sample of 226.0 +/- 2.5 million B (B) over bar pairs collected by the BABAR detector. We measure the total branching fraction and CP asymmetry to be B=(35.2 +/- 0.9 +/- 1.6)x10(-6) and A(CP)=(-1.7 +/- 2.6 +/- 1.5)%. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of CP violation for the individual components of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for which we perform a partial-wave analysis in the region m(K+K-)< 2 GeV/c(2). Significant production of the f(0)(980) resonance, and of a spin zero state near 1.55 GeV/c(2) are required in the isobar model description of the data. The partial-wave analysis supports this observation.This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (The Netherlands), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from CONACyT (Mexico), Marie Curie EIF (European Union), the A. P. Sloan Foundation, the Research Corporation, and the Alexander von Humboldt Foundation

    Branching fraction measurements of B+->rho(+)gamma, B-0 ->rho(0)gamma, and B-0 ->omega gamma

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    We present a study of the decays B+->rho(+)gamma, B-0 ->rho(0)gamma, and B-0 ->omega gamma. The analysis is based on data containing 347x10(6) B (B) over bar events recorded with the BABAR detector at the PEP-II asymmetric B factory. We measure the branching fractions B(B+->rho(+)gamma)=(1.10(-0.33)(+0.37)+/- 0.09)x10(-6) and B(B-0 ->rho(0)gamma)=(0.79(-0.20)(+0.22)+/- 0.06)x10(-6), and set a 90% C.L. upper limit B(B-0 ->omega gamma)(rho/omega)gamma)=(1.25(-0.24)(+0.25)+/- 0.09)x10(-6), from which we determine vertical bar V-td/V-ts vertical bar=0.200(-0.020)(+0.021)+/- 0.015, where the first uncertainty is experimental and the second is theoretical

    Measurement of the CP asymmetry and branching fraction of B-0 ->rho K-0(0)

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    We present a measurement of the branching fraction and time-dependent CP asymmetry of B-0 -> POKO. The results are obtained from a data sample of 227 x 10(6) Y(4S) -> BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at Stanford Linear Accelerator Center. From a time-dependent maximum likelihood fit yielding 111 +/- 19 signal events, we find B(B-0 -> rho K-0(0)) = (4.9 +/- 0.8 +/- 0.9) x 10(-6), where the first error is statistical and the second systematic. We report the measurement of the CP parameters S-rho 0KS0 = 0.20 +/- 0.52 +/- 0.24 and C-rho 0KS0 = 0.64 +/- 0.41 +/- 0.20

    Measurement of branching fractions and charge asymmetries in B decays to an eta meson and a K-* meson

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    We present measurements of branching fractions and charge asymmetries for the decays B ->eta K-*, where K-* indicates a spin 0, 1, or 2 K pi system. The data sample corresponds to 344x10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We measure the branching fractions (in units of 10(-6)): B(B-0 ->eta K-*0(892))=16.5 +/- 1.1 +/- 0.8, B(B+->eta K*+(892))=18.9 +/- 1.8 +/- 1.3, B(B-0 ->eta(K pi)(0)(*0))=11.0 +/- 1.6 +/- 1.5, B(B+->eta(K pi)(0)(*+))=18.2 +/- 2.6 +/- 2.6, B(B-0 ->eta K-2(*0)(1430))=9.6 +/- 1.8 +/- 1.1, and B(B+->eta K-2(*+)(1430))=9.1 +/- 2.7 +/- 1.4. We also determine the charge asymmetries for all decay modes
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