25,798,797 research outputs found

    Color suppressed contributions to the decay modes B_{d,s} -> D_{s,d} D_{s,d}, B_{d,s} -> D_{s,d} D^*_{s,d}, and B_{d,s} -> D^*_{s,d} D^*_{s,d}

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    The amplitudes for decays of the type Bd,sDs,dDs,dB_{d,s} \to D_{s,d} D_{s,d}, have no factorizable contributions, while Bd,sDs,dDs,dB_{d,s} \to D_{s,d} D^*_{s,d}, and Bd,sDs,dDs,dB_{d,s} \to D^*_{s,d} D^*_{s,d} have relatively small factorizable contributions through the annihilation mechanism. The dominant contributions to the decay amplitudes arise from chiral loop contributions and tree level amplitudes which can be obtained in terms of soft gluon emissions forming a gluon condensate. We predict that the branching ratios for the processes Bˉd0Ds+Ds\bar B^0_d \to D_s^+ D_s^-, Bˉd0Ds+Ds\bar B^0_d \to D_s^{+*} D_s^- and Bˉd0Ds+Ds\bar B^0_d \to D_s^+ D_s^{-*} are all of order (23)×104(2- 3) \times 10^{-4}, while Bˉs0Dd+Dd\bar B^0_s \to D_d^+ D_d^-, Bˉs0Dd+Dd\bar B^0_s \to D_d^{+*} D_d^- and Bˉs0Dd+Dd\bar B^0_s \to D_d^+ D_d^{-*} are of order (47)×103(4- 7) \times 10^{-3}. We obtain branching ratios for two DD^*'s in the final state of order two times bigger.Comment: 15 pages, 4 figure

    Observation of B0D+DB^0 \to D^+ D^-, BD0DB^- \to D^0 D^- and BD0DB^- \to D^0 D^{*-} decays

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    We report the first observation of the decay modes B0D+DB^0 \to D^+ D^-, BD0DB^- \to D^0 D^- and BD0DB^- \to D^0 D^{*-} based on 152 ×\times 106^6 BBˉB\bar{B} events collected at KEKB. The branching fractions of B0D+DB^0 \to D^+ D^-, BD0DB^- \to D^0 D^- and BD0DB^- \to D^0 D^{*-} are found to be (3.21±0.57±0.48)×104(3.21 \pm 0.57 \pm 0.48) \times 10^{-4}, (5.62±0.82±0.65)×104(5.62 \pm 0.82 \pm 0.65) \times 10^{-4} and (4.59±0.72±0.56)×104(4.59 \pm 0.72 \pm 0.56) \times 10^{-4}, respectively. Charge asymmetries in the BD0DB^- \to D^0 D^- and BD0DB^- \to D^0 D^{*-} channels are consistent with zero.Comment: 9 pages, 2 figures, KEK Preprint 2004-99, Belle Prerpint 2005-3, submitted to PR

    Dynamic Geospatial Spectrum Modelling: Taxonomy, Options and Consequences

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    Much of the research in Dynamic Spectrum Access (DSA) has focused on opportunistic access in the temporal domain. While this has been quite useful in establishing the technical feasibility of DSA systems, it has missed large sections of the overall DSA problem space. In this paper, we argue that the spatio-temporal operating context of specific environments matters to the selection of the appropriate technology for learning context information. We identify twelve potential operating environments and compare four context awareness approaches (on-board sensing, databases, sensor networks, and cooperative sharing) for these environments. Since our point of view is overall system cost and efficiency, this analysis has utility for those regulators whose objectives are reducing system costs and enhancing system efficiency. We conclude that regulators should pay attention to the operating environment of DSA systems when determining which approaches to context learning to encourage

    Scholarly Communication and Publishing Lunch and Learn Talks

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    This series of talks focuses on issues in scholarly communication and publishing presented to University Library System (ULS), University of Pittsburgh colleagues by staff members of the ULS Office of Scholarly Communication and Publishing. Many of these talks feature "toolbox" tips on how to apply knowledge gained from the talks. Links to recordings of the talks are provided when available. For topics and presentations, see the record for each talk

    Surgical technique of orthotopic liver transplantation

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    Athough significant strides have been made in the surgical technique of orthotopic liver transplantation, numerous problems and nuisances are still encountered. Further surgical refinements will certainly evolve. The development of better preservation techniques, the use of intraoperative flowmeters, and the availability of new technologies, such as an artificial liver, should impact and advance the techniques of liver transplantation significantly and improve the overall results even further

    D-Strings on D-Manifolds

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    We study the mechanism for appearance of massless solitons in type II string compactifications. We find that by combining TT-duality with strong/weak duality of type IIB in 10 dimensions enhanced gauge symmetries and massless solitonic hypermultiplets encountered in Calabi-Yau compactifications can be studied perturbatively using D-strings (the strong/weak dual to type IIB string) compactified on ``D-manifolds''. In particular the nearly massless solitonic states of the type IIB compactifications correspond to elementary states of D-strings. As examples we consider the D-string description of enhanced gauge symmetries for type IIA string compactification on ALE spaces with AnA_n singularities and type IIB on a class of singular Calabi-Yau threefolds. The class we study includes as a special case the conifold singularity in which case the perturbative spectrum of the D-string includes the expected massless hypermultiplet with degeneracy one.Comment: 23 pages, with 3 figures. A compact example is adde

    DYNAMITE: ANARCHISM, MODERNISM, AESTHETICS

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    This book argues for the intersection of anarchist theory, modernist writers, and aesthetic innovations under the sign of "the bomb." Individual chapters concern such figures as Joseph Conrad, Richard Wagner, Henry Adams, Andrei Bely, Edna St. Vincent Millay, Upton Sinclair, John Dos Passos, and Katherine Ann Porter, as well as collectivities like the Surrealists and the Dadaists. Anarchists such as Peter Kropotkin, Emma Goldman, and Michael Bakunin are also important to the text. The original version of this text was produced as a dissertation at the University of California Berkeley. Committee members were Carolyn Porter, Ann Banfield, and the late Michael Rogin. Three chapters--those on Conrad, Wagner, and the Sacco-Vanzetti case--were published in refereed academic journals. A synopsis of the argument was published in The Turn of the Century, Walter Pape, editor (Berlin and New York: Walter de Gruyter) 1995. Dynamite had been approved for publication in the Atopia series of Stanford University Press when major changes at the press resulted in the abolition of the series
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