29,743 research outputs found

    Lepton flavor violating liljγγl_i\to l_j \gamma\gamma decays induced by scalar unparticle

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    We study the radiative lepton flavor violating l_i -> l_j \gamma\gamma decays in the case that the lepton flavor violation is induced by the scalar unparticle mediation. We restrict the scaling dimension d_u and the scalar unparticle-photon-photon coupling by using the experimental upper limit of the branching ratio of the decay \mu -> e \gamma\gamma. Furthermore, we predict the BRs of the other radiative decays by using the restrictions we get. We observe that the measurements of upper limits of BRs of these decays ensure considerable information for testing the possible signals coming from unparticle physicsComment: 10 pages, 5 figures, 1 tabl

    The XYZs of Charmonium at BES

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    This contribution reviews some recent developments in charmonium spectroscopy, and discusses related theoretical predictions. The spectrum of states, strong decays of states above open charm threshold, electromagnetic transitions, and issues related to the recent discoveries of the "XYZ" states are discussed. Contributions that BES can make to our understanding of charmonium and related states are stressed in particular.Comment: 5 pages, 1 eps figure. Invited contribution to the International Workshop on Tau-Charm Physics Charm2006 (5-7 June 2006, Beijing, China

    Properties of Scalar-Quark Systems in SU(3)c Lattice QCD

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    We perform the first study for the bound states of colored scalar particles ϕ\phi ("scalar quarks") in terms of mass generation with quenched SU(3)c_c lattice QCD. We investigate the bound states of ϕ\phi, ϕϕ\phi^\dagger\phi and ϕϕϕ\phi\phi\phi ("scalar-quark hadrons"), as well as the bound states of ϕ\phi and quarks ψ\psi, i.e., ϕψ\phi^\dagger\psi, ψψϕ\psi\psi\phi and ϕϕψ\phi\phi\psi ("chimera hadrons"). All these new-type hadrons including ϕ\phi have a large mass of several GeV due to large quantum corrections by gluons, even for zero bare scalar-quark mass mϕ=0m_\phi=0 at a11GeVa^{-1}\sim 1{\rm GeV}. We find a similar mψm_\psi-dependence between ϕψ\phi^\dagger\psi and ϕϕψ\phi\phi\psi, which indicates their similar structure due to the large mass of ϕ\phi. From this study, we conjecture that all colored particles generally acquire a large effective mass due to dressed gluons

    New neighborhood based rough sets

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    Neighborhood based rough sets are important generalizations of the classical rough sets of Pawlak, as neighborhood operators generalize equivalence classes. In this article, we introduce nine neighborhood based operators and we study the partial order relations between twenty-two different neighborhood operators obtained from one covering. Seven neighborhood operators result in new rough set approximation operators. We study how these operators are related to the other fifteen neighborhood based approximation operators in terms of partial order relations, as well as to seven non-neighborhood-based rough set approximation operators

    Exploring Deep Space: Learning Personalized Ranking in a Semantic Space

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    Recommender systems leverage both content and user interactions to generate recommendations that fit users' preferences. The recent surge of interest in deep learning presents new opportunities for exploiting these two sources of information. To recommend items we propose to first learn a user-independent high-dimensional semantic space in which items are positioned according to their substitutability, and then learn a user-specific transformation function to transform this space into a ranking according to the user's past preferences. An advantage of the proposed architecture is that it can be used to effectively recommend items using either content that describes the items or user-item ratings. We show that this approach significantly outperforms state-of-the-art recommender systems on the MovieLens 1M dataset.Comment: 6 pages, RecSys 2016 RSDL worksho

    Influence of low-level Pr substitution on the superconducting properties of YBa2Cu3O7-delta single crystals

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    We report on measurements on Y1-xPrxBa2Cu3O7-delta single crystals, with x varying from 0 to 2.4%. The upper and the lower critical fields, Hc2 and Hc1, the Ginzburg-Landau parameter and the critical current density, Jc(B), were determined from magnetization measurements and the effective media approach scaling method. We present the influence of Pr substitution on the pinning force density as well as on the trapped field profiles analyzed by Hall probe scanning.Comment: 4 pages, 5 figures, accepted for publication in J. Phys. Conf. Se
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