21,015 research outputs found

    Unification of Flavor SU(3) Analyses of Heavy Hadron Weak Decays

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    Analyses of heavy mesons and baryons hadronic charmless decays using the flavor SU(3) symemtry can be formulated in two different forms. One is to construct the SU(3) irreducible representation amplitude (IRA) by decomposing effective Hamiltonian, and the other is to draw the topological diagrams (TDA). In the flavor SU(3) limit, we study various B/D→PP,VP,VVB/D\to PP,VP,VV, Bc→DP/DVB_c\to DP/DV decays, and two-body nonleptonic decays of beauty/charm baryons, and demonstrate that when all terms are included these two ways of analyzing the decay amplitudes are completely equivalent. Furthermore we clarify some confusions in drawing topological diagrams using different ways of describing beauty/charm baryons.Comment: 36 pages, 6 figures, 16 table

    Weak Decays of Doubly Heavy Baryons: Multi-body Decay Channels

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    The newly-discovered Ξcc++\Xi_{cc}^{++} decays into the Λc+K−π+π+ \Lambda_{c}^+ K^-\pi^+\pi^+, but the experimental data has indicated that this decay is not saturated by any two-body intermediate state. In this work, we analyze the multi-body weak decays of doubly heavy baryons Ξcc\Xi_{cc}, Ωcc\Omega_{cc}, Ξbc\Xi_{bc}, Ωbc\Omega_{bc}, Ξbb\Xi_{bb} and Ωbb\Omega_{bb}, in particular the three-body nonleptonic decays and four-body semileptonic decays. We classify various decay modes according to the quark-level transitions and present an estimate of the typical branching fractions for a few golden decay channels. Decay amplitudes are then parametrized in terms of a few SU(3) irreducible amplitudes. With these amplitudes, we find a number of relations for decay widths, which can be examined in future.Comment: 47pages, 1figure. arXiv admin note: substantial text overlap with arXiv:1707.0657

    Sparse regression models for unraveling group and individual associations in eQTL mapping

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    BackgroundAs a promising tool for dissecting the genetic basis of common diseases, expression quantitative trait loci (eQTL) study has attracted increasing research interest. Traditional eQTL methods focus on testing the associations between individual single-nucleotide polymorphisms (SNPs) and gene expression traits. A major drawback of this approach is that it cannot model the joint effect of a set of SNPs on a set of genes, which may correspond to biological pathways.ResultsTo alleviate this limitation, in this paper, we propose geQTL, a sparse regression method that can detect both group-wise and individual associations between SNPs and expression traits. geQTL can also correct the effects of potential confounders. Our method employs computationally efficient technique, thus it is able to fulfill large scale studies. Moreover, our method can automatically infer the proper number of group-wise associations. We perform extensive experiments on both simulated datasets and yeast datasets to demonstrate the effectiveness and efficiency of the proposed method. The results show that geQTL can effectively detect both individual and group-wise signals and outperforms the state-of-the-arts by a large margin.ConclusionsThis paper well illustrates that decoupling individual and group-wise associations for association mapping is able to improve eQTL mapping accuracy, and inferring individual and group-wise associations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12859-016-0986-9) contains supplementary material, which is available to authorized users
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