4,403 research outputs found

    Weak Decays of Heavy-Light Mesons on the Lattice: Semi-Leptonic Formfactors

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    We report results (on an intermediate statistics sample) of a study of weak semi-leptonic formfactors of BB and DD decays, addressing the uncertainties from mass extrapolations to chiral and to heavy quarks. Moreover, we present a nonperturbative test to the LMK current renormalization scheme for vector current {\it transition} matrix elements and find remarkable agreement.Comment: 13 pages, uuencoded, updated table

    Radio-Echo Sounding Over Polar Ice Masses

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    Semileptonic Decays of D and B Mesons

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    We report results of our ongoing investigation concerning semileptonic decays of heavy pseudoscalar mesons into pseudoscalar and vector mesons. Particular attention is paid to uncertainties in the q2q^2 and the heavy quark mass dependence of formfactors. Moreover we present a non-perturbative test to the LMK current renormalization scheme for vector current transition matrix elements and find remarkable agreement.Comment: 3 pages, uuencoded, contribution to Lat 9

    The 26^{26}Al Gamma-ray Line from Massive-Star Regions

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    The measurement of gamma rays from the diffuse afterglow of radioactivity originating in massive-star nucleosynthesis is considered a laboratory for testing models, when specific stellar groups are investigated, at known distance and with well-constrained stellar population. Regions which have been exploited for such studies include Cygnus, Carina, Orion, and Scorpius-Centaurus. The Orion region hosts the Orion OB1 association and its subgroups at about 450~pc distance. We report the detection of 26^{26}Al gamma rays from this region with INTEGRAL/SPI.Comment: Contribution to Symposium "Nuclei in the Cosmos XIV", Niigata, Japan, Jun 2016; 3 pages, 2 figures; accepted for publication in JPS (Japan Physical Society) Conference Proceedings http://jpscp.jps.jp

    Beautiful Baryons from Lattice QCD

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    We perform a lattice study of heavy baryons, containing one (Λb\Lambda_b) or two bb-quarks (Ξb\Xi_b). Using the quenched approximation we obtain for the mass of Λb\Lambda_b MΛb=5.728±0.144±0.018GeV. M_{\Lambda_b}= 5.728 \pm 0.144 \pm 0.018 {\rm GeV}. The mass splitting between the Λb\Lambda_b and the B-meson is found to increase by about 20\% if the light quark mass is varied from the chiral limit to the strange quark mass.Comment: 11 pages, Figures obtained upon request from [email protected]

    Semileptonic Decays of Heavy Mesons: A Status Report

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    We present intermediate results on our ongoing investigation concerning semileptonic decays of heavy pseudoscalar mesons into pseudoscalar and vector mesons. The corresponding formfactors are evaluated at several momenta and appropriate combinations of four light and four heavy quarks, which are chosen to allow for an extrapolation into the B Meson region. In order to obtain clear groundstate signals we apply gauge invariant ``Wuppertal'' smearing to the quarks. The analysis is based on 32 quenched gauge configurations of size 243×6424^3 \times 64 at β=6.3\beta=6.3, with Wilson fermions.Comment: 3 pages, uuencoded, contribution to Lat 9

    Light Spectrum and Decay Constants in Full QCD with Wilson Fermions

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    We present results from an analysis of the light spectrum and the decay constants f_{\pi} and f_V^{-1} in Full QCD with n_f=2 Wilson fermions at a coupling of beta=5.6 on a 16^3x32 lattice.Comment: 3 pages, LaTeX with 4 eps figures, Talk presented at LATTICE96(spectrum

    A Bayesian framework for verification and recalibration of ensemble forecasts: How uncertain is NAO predictability?

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    Predictability estimates of ensemble prediction systems are uncertain due to limited numbers of past forecasts and observations. To account for such uncertainty, this paper proposes a Bayesian inferential framework that provides a simple 6-parameter representation of ensemble forecasting systems and the corresponding observations. The framework is probabilistic, and thus allows for quantifying uncertainty in predictability measures such as correlation skill and signal-to-noise ratios. It also provides a natural way to produce recalibrated probabilistic predictions from uncalibrated ensembles forecasts. The framework is used to address important questions concerning the skill of winter hindcasts of the North Atlantic Oscillation for 1992-2011 issued by the Met Office GloSea5 climate prediction system. Although there is much uncertainty in the correlation between ensemble mean and observations, there is strong evidence of skill: the 95% credible interval of the correlation coefficient of [0.19,0.68] does not overlap zero. There is also strong evidence that the forecasts are not exchangeable with the observations: With over 99% certainty, the signal-to-noise ratio of the forecasts is smaller than the signal-to-noise ratio of the observations, which suggests that raw forecasts should not be taken as representative scenarios of the observations. Forecast recalibration is thus required, which can be coherently addressed within the proposed framework.Comment: 36 pages, 10 figure

    Die Zukunft der Werbung im Ländervergleich

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    Welche Werbeformen und formate werden im internationalen Vergleich am häufigsten eingesetzt? Wie unterscheidet sich in ausgesuchten Ländern die Gesamtsituation der Werbung und wie wird sie sich entwickeln? Ist personalisierte Online-Werbung die Werbung der Zukunft oder werden die Werbegelder auch künftig noch in klassische Medien investiert? Das Buch untersucht die aktuelle Situation und die Entwicklung der Werbung in ausgewählten Ländern auf Basis der I/P-Matrix sowie anhand von Strukturdaten und explorativen Experteninterviews. Daraus entsteht ein Gesamteindruck davon, wie sich Werbung in Australien, China, Deutschland, Indien, Italien, Österreich, Russland, Schweden, der Schweiz, Thailand, den USA und UK aktuell präsentiert und welche Entwicklungslinien sich für die Werbung in diesen Ländern abzeichnen
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