69 research outputs found

    Study of the B^0 Semileptonic Decay Spectrum at the Upsilon(4S) Resonance

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    We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B0 --> D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the Upsilon(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Upsilon(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B0 and B+ semileptonic branching fractions, b0 and b+, their ratio, and the production ratio f+-/f00 of B+ and B0 pairs at the Upsilon(4S). We report b+/b0=0.950 (+0.117-0.080) +- 0.091, b0 = (10.78 +- 0.60 +- 0.69)%, and b+ = (10.25 +- 0.57 +- 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes, tau+/tau0.Comment: 14 page, postscript file also available at http://w4.lns.cornell.edu/public/CLN

    Observation of the Ξc+\Xi_c^+ Charmed Baryon Decays to ÎŁ+K−π+\Sigma^+ K^-\pi^+, ÎŁ+Kˉ∗0\Sigma^+ \bar{K}^{*0}, and ΛK−π+π+\Lambda K^-\pi^+\pi^+

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    We have observed two new decay modes of the charmed baryon Ξc+\Xi_c^+ into ÎŁ+K−π+\Sigma^+ K^-\pi^+ and ÎŁ+Kˉ∗0\Sigma^+ \bar{K}^{*0} using data collected with the CLEO II detector. We also present the first measurement of the branching fraction for the previously observed decay mode Ξc+→ΛK−π+π+\Xi_c^+\to\Lambda K^-\pi^+\pi^+. The branching fractions for these three modes relative to Ξc+→Ξ−π+π+\Xi_c^+\to\Xi^-\pi^+\pi^+ are measured to be 1.18±0.26±0.171.18 \pm 0.26 \pm 0.17, 0.92±0.27±0.140.92 \pm 0.27 \pm 0.14, and 0.58±0.16±0.070.58 \pm 0.16 \pm 0.07, respectively.Comment: 12 page uuencoded postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurements of the Ratios B(Ds+→ηℓ+Îœ)/B(Ds+→ϕℓ+Îœ){\cal B}(D_s^+\to \eta\ell^+\nu)/{\cal B}(D_s^+\to \phi\ell^+\nu) and B(Ds+→ηâ€Čℓ+Îœ)/B(Ds+→ϕℓ+Îœ){\cal B}(D_s^+\to \eta'\ell^+\nu)/{\cal B}(D_s^+\to \phi\ell^+\nu)

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    Using the CLEO~II detector we measure B(Ds+→ηe+Îœ)/B(Ds+→ϕe+Îœ)=1.24±0.12±0.15{\cal B}(D_s^+\to \eta e^+\nu)/{\cal B}(D_s^+\to \phi e^+\nu) =1.24\pm0.12\pm0.15, B(Ds+→ηâ€Če+Îœ)/B(Ds+→ϕe+Îœ)=0.43±0.11±0.07{\cal B}(D_s^+\to \eta' e^+\nu)/{\cal B}(D_s^+\to \phi e^+\nu) =0.43\pm0.11\pm0.07 and B(Ds+→ηâ€Če+Îœ)/B(Ds+→ηe+Îœ)=0.35±0.09±0.07{\cal B}(D_s^+\to \eta' e^+\nu)/{\cal B}(D_s^+\to \eta e^+\nu) =0.35\pm0.09\pm0.07. We find the vector to pseudoscalar ratio, B(Ds+→ϕe+Îœ)/B(Ds+→(η+ηâ€Č)e+Îœ)=0.60±0.06±0.06{\cal B}(D_s^+\to \phi e^+\nu)/{\cal B}(D_s^+\to (\eta+\eta') e^+\nu) =0.60\pm0.06\pm0.06, which is similar to the ratio found in non strange DD decays.Comment: 11 page uuencoded postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Radiative Decay Modes of the D0D^{0} Meson

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    Using data recorded by the CLEO-II detector at CESR we have searched for four radiative decay modes of the D0D^0 meson: D0â†’Ï•ÎłD^0\to\phi\gamma, D0â†’Ï‰ÎłD^0\to\omega\gamma, D0→Kˉ∗γD^0\to\bar{K}^{*}\gamma, and D0→ρ0ÎłD^0\to\rho^0\gamma. We obtain 90% CL upper limits on the branching ratios of these modes of 1.9×10−41.9\times 10^{-4}, 2.4×10−42.4\times 10^{-4}, 7.6×10−47.6\times 10^{-4} and 2.4×10−42.4\times 10^{-4} respectively.Comment: 15 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of the Mass Splittings between the bbˉχb,J(1P)b\bar{b}\chi_{b,J}(1P) States

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    We present new measurements of photon energies and branching fractions for the radiative transitions: Upsilon(2S)->gamma+chi_b(J=0,1,2). The masses of the chi_b states are determined from the measured radiative photon energies. The ratio of mass splittings between the chi_b substates, r==(M[J=2]-M[J=1])/(M[J=1]-M[J=0]) with M the chi_b mass, provides information on the nature of the bbbar confining potential. We find r(1P)=0.54+/-0.02+/-0.02. This value is in conflict with the previous world average, but more consistent with the theoretical expectation that r(1P)<r(2P); i.e., that this mass splittings ratio is smaller for the chi_b(1P) triplet than for the chi_b(2P) triplet.Comment: 11 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Sustainability Science

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    Meeting fundamental human needs while preserving earth's life support systems will require an accelerated transition toward sustainability. A new field of sustainability science is emerging that seeks to understand the fundamental character of interactions between nature and society and to encourage the interactions along more sustainable trajectories. Such an integrated, place-based science will require new research strategies and institutional innovations to enable them especially in developing countries still separated by deepening divides from mainstream science. Sustainability science needs to be widely discussed in the scientific community, reconnected to the political agenda for sustainable development, and become a major focus for research

    Studies of the Cabbibo-Suppressed Decays D+→π0ℓ+ÎœD^+ \to \pi^0 \ell^+ \nu and D+→ηe+ÎœeD^+ \to \eta e^+ \nu_e

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    Using 4.8 fb−1^{-1} of data taken with the CLEO II detector, the branching fraction for the Cabibbo-suppressed decay D+→π0ℓ+ÎœD^+\to\pi^0\ell^+\nu measured relative to the Cabibbo favored decay D+→K0ˉℓ+ÎœD^+\to\bar{K^0}\ell^+\nu is found to be 0.046±0.014±0.0170.046\pm 0.014\pm 0.017. Using VcsV_{cs} and VcdV_{cd} from unitarity constraints, we determine ∣f+π(0)/f+K(0)∣2=0.9±0.3±0.3| f_+^{\pi}(0)/f_+^K(0)|^2=0.9\pm 0.3\pm 0.3 We also present a 90% confidence level upper limit for the branching ratio of the decay D+→ηe+ÎœeD^+ \to \eta e^+\nu_e relative to that for D+→π0e+ÎœeD^+ \to \pi^0 e^+\nu_e of 1.5.Comment: 10 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of B→ρℓΜB\to \rho\ell\nu Decay and ∣Vub∣|V_{ub}|

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    Using a sample of 3.3 million Upsilon(4S) -> BBbar events collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR), we measure the branching fraction for B -> rho l nu, |V_ub|, and the partial rate (Delta Gamma) in three bins of q^2 = (p_B-p_rho)^2. We find B(B^0 -> rho^- l^+ nu)=(2.69 +- 0.41^+0.35_-0.40 +- 0.50) 10^-4, |V_ub|=(3.23 +- 0.24^+0.23_-0.26 +- 0.58) 10^-3, Delta Gamma (0 < q^2 < 7 GeV^2/c^4) =(7.6 +- 3.0 ^+0.9_-1.2 +- 3.0) 10^-2 ns^-1, Delta Gamma (7 < q^2 < 14 GeV^2/c^4) =(4.8 +- 2.9 ^+0.7_-0.8 +- 0.7) 10^-2 ns^-1, and Delta Gamma (14 < q^2 < 21 GeV^2/c^4) = (7.1 +- 2.1^+0.9_-1.1 +- 0.6)10^-2 ns^-1. The quoted errors are statistical, systematic, and theoretical. The method is sensitive primarily to B -> rho l nu decays with leptons in the energy range above 2.3 GeV. Averaging with the previously published CLEO results, we obtain B(B^0 -> rho^- l^+ nu) = (2.57 +- 0.29^+0.33_-0.46 +- 0.41) 10^-4 and |V_{ub}| = (3.25 +- 0.14 ^+0.21_-0.29 +- 0.55) 10^-3.Comment: 35 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    The epitaxy of gold

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    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
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