934 research outputs found

    D0−Dˉ0D^0-\bar{D}^0 mixing studies with the decays D0→KS0K∓π±D^0 \to K^0_S K^\mp \pi^\pm

    Get PDF
    We demonstrate how a time-dependent analysis of the decays D0→KS0K∓π±D^0 \to K^0_S K^\mp \pi^\pm can be used to determine the D0−Dˉ0D^0-\bar{D}^0 mixing parameter yy with a precision that is competitive with established methods. The proposed analysis is an inclusive study which makes use of the measurements of the coherence factor and mean strong phase difference for these decays recently performed by CLEO.Comment: 9 pages, 1 figure. Journal reference added. Minor typos fixe

    Averages of bb-hadron, cc-hadron, and τ\tau-lepton properties as of summer 2014

    Full text link
    This article reports world averages of measurements of bb-hadron, cc-hadron, and τ\tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through summer 2014. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CPCP violation parameters, parameters of semileptonic decays and CKM matrix elements.Comment: 436 pages, many figures and tables. Online updates available at http://www.slac.stanford.edu/xorg/hfag

    Population variation in brain size of nine-spined sticklebacks (Pungitius pungitius) - local adaptation or environmentally induced variation?

    Get PDF
    Abstract Background Most evolutionary studies on the size of brains and different parts of the brain have relied on interspecific comparisons, and have uncovered correlations between brain architecture and various ecological, behavioural and life-history traits. Yet, similar intraspecific studies are rare, despite the fact that they could better determine how selection and phenotypic plasticity influence brain architecture. We investigated the variation in brain size and structure in wild-caught nine-spined sticklebacks (Pungitius pungitius) from eight populations, representing marine, lake, and pond habitats, and compared them to data from a previous common garden study from a smaller number of populations. Results Brain size scaled hypo-allometrically with body size, irrespective of population origin, with a common slope of 0.5. Both absolute and relative brain size, as well as relative telencephalon, optic tectum and cerebellum size, differed significantly among the populations. Further, absolute and relative brain sizes were larger in pond than in marine populations, while the telencephalon tended to be larger in marine than in pond populations. These findings are partly incongruent with previous common garden results. A direct comparison between wild and common garden fish from the same populations revealed a habitat-specific effect: pond fish had relatively smaller brains in a controlled environment than in the wild, while marine fish were similar. All brain parts were smaller in the laboratory than in the wild, irrespective of population origin. Conclusion Our results indicate that variation among populations is large, both in terms of brain size and in the size of separate brain parts in wild nine-spined sticklebacks. However, the incongruence between the wild and common garden patterns suggests that much of the population variation found in the wild may be attributable to environmentally induced phenotypic plasticity. Given that the brain is among the most plastic organs in general, the results emphasize the view that common garden data are required to draw firm evolutionary conclusions from patterns of brain size variability in the wild.</p

    Observation of D0−Dˉ0D^0-\bar{D}^0 Mixing in e+e−e^+e^- Collisions

    Full text link
    We observe D0−Dˉ0D^0-\bar{D}^0 mixing in the decay D0→K+π−D^0\rightarrow K^+\pi^- using a data sample of integrated luminosity 976 fb−1^{-1} collected with the Belle detector at the KEKB e+e−e^+e^- asymmetric-energy collider. We measure the mixing parameters xâ€Č2=(0.09±0.22)×10−3{x'}^2 = (0.09\pm0.22)\times 10^{-3} and yâ€Č=(4.6±3.4)×10−3y' = (4.6\pm3.4)\times 10^{-3} and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates RD=(3.53±0.13)×10−3R_D = (3.53\pm0.13)\times 10^{-3}, where the uncertainties are statistical and systematic combined. Our measurement excludes the no-mixing hypothesis at the 5.1 standard deviation level.Comment: 6 pages, 4 figure

    Search for leptonic decays of D0 mesons

    Full text link
    We search for the flavor-changing neutral current decays D0\to mu+mu- and D0\to e+e-, and for the lepton-flavor violating decays D0\to e\pm mu\mp using 660 fb^-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We find no evidence for any of these decays. We obtain significantly improved upper limits on the branching fractions: B(D0\to mu+mu-)<1.4x10-7, B(D0\to e+e-)<7.9x10-8, and B(D0\to e+mu-)+B(D0\to mu+e-)<2.6x10-7 at 90% confidence level.Comment: 6 pages, 3 figure

    Time-dependent CP Asymmetries in B0→KS0ρ0ÎłB^0\to K^0_S\rho^0\gamma Decays

    Full text link
    We report the first measurement of CP-violation parameters in B^0 -> K_S^0\rho^0\gamma decays based on 657 million B\bar B pairs collected with the Belle detector at the KEKB asymmetric-energy collider. We measure the time-dependent CP violating parameter S_{K_S^0\rho^0\gamma}= 0.11 +/- 0.33(stat.)^{+0.05}_{-0.09}(syst.). We also obtain the effective direct CP violating parameter A_eff=0.05 +/- 0.18(stat.) +/- 0.06(syst.) for m_{K_S\pi^+\pi^-}<1.8 GeV/c^2 and 0.6 GeV/c^2<m_{\pi^+\pi^-}<0.9 GeV/c^2.Comment: 6 pages, 3 figures, to be submitted to PR

    Search for B→πℓ+ℓ−B \to \pi \ell^+\ell^- Decays at Belle

    Full text link
    We present a search for the B-> pi e^+ e^- and B-> pi \mu^+ \mu^- decays, with a data sample of 657 million BBbar pairs collected with the Belle detector at the KEKB e+e−e^+e^- collider. Signal events are reconstructed from a charged or a neutral pion candidate and a pair of oppositely charged electrons or muons. No significant signal is observed and we set the upper limit on the isospin-averaged branching fraction BF(B -> \pi \ell^+\ell^-) < 6.2x10^-8 at the 90% confidence level.Comment: 8 pages, 3 figures, accepted by PRD(RC
    • 

    corecore