7,008 research outputs found

    Quantum Electroweak Symmetry Breaking Through Loop Quadratic Contributions

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    Based on two postulations that (i) the Higgs boson has a large bare mass mH≫mh≃125m_H \gg m_h \simeq 125 GeV at the characteristic energy scale McM_c which defines the standard model (SM) in the ultraviolet region, and (ii) quadratic contributions of Feynman loop diagrams in quantum field theories are physically meaningful, we show that the SM electroweak symmetry breaking is induced by the quadratic contributions from loop effects. As the quadratic running of Higgs mass parameter leads to an additive renormalization, which distinguishes from the logarithmic running with a multiplicative renormalization, the symmetry breaking occurs once the sliding energy scale ΞΌ\mu moves from McM_c down to a transition scale ΞΌ=Ξ›EW\mu =\Lambda_{EW} at which the additive renormalized Higgs mass parameter mH2(Mc/ΞΌ)m^2_H(M_c/\mu) gets to change the sign. With the input of current experimental data, this symmetry breaking energy scale is found to be Ξ›EW≃760\Lambda_{EW}\simeq 760 GeV, which provides another basic energy scale for the SM besides McM_c. Studying such a symmetry breaking mechanism could play an important role in understanding both the hierarchy problem and naturalness problem. It also provides a possible way to explore the experimental implications of the quadratic contributions as Ξ›EW\Lambda_{EW} lies within the probing reach of the LHC and the future Great Collider.Comment: 10 pages, 2 figures, published versio

    End-to-end Learning for Short Text Expansion

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    Effectively making sense of short texts is a critical task for many real world applications such as search engines, social media services, and recommender systems. The task is particularly challenging as a short text contains very sparse information, often too sparse for a machine learning algorithm to pick up useful signals. A common practice for analyzing short text is to first expand it with external information, which is usually harvested from a large collection of longer texts. In literature, short text expansion has been done with all kinds of heuristics. We propose an end-to-end solution that automatically learns how to expand short text to optimize a given learning task. A novel deep memory network is proposed to automatically find relevant information from a collection of longer documents and reformulate the short text through a gating mechanism. Using short text classification as a demonstrating task, we show that the deep memory network significantly outperforms classical text expansion methods with comprehensive experiments on real world data sets.Comment: KDD'201

    Determinations of form factors for semileptonic D→KD\rightarrow K decays and leptoquark constraints

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    By analyzing all existing measurements for Dβ†’Kβ„“+Ξ½β„“ D\rightarrow K \ell^+ \nu_{\ell} ( β„“=e,Β ΞΌ\ell=e,\ \mu ) decays, we find that the determinations of both the vector form factor f+K(q2)f_+^K(q^2) and scalar form factor f0K(q2)f_0^K(q^2) for semileptonic Dβ†’KD\rightarrow K decays from these measurements are feasible. By taking the parameterization of the one order series expansion of the f+K(q2)f_+^K(q^2) and f0K(q2)f_0^K(q^2), f+K(0)∣Vcs∣f_+^K(0)|V_{cs}| is determined to be 0.7182Β±0.00290.7182\pm0.0029, and the shape parameters of f+K(q2)f_+^K(q^2) and f0K(q2)f_0^K(q^2) are r+1=βˆ’2.16Β±0.007r_{+1}=-2.16\pm0.007 and r01=0.89Β±3.27r_{01}=0.89\pm3.27, respectively. Combining with the average f+K(0)f_+^K(0) of Nf=2+1N_f=2+1 and Nf=2+1+1N_f=2+1+1 lattice calculaltion, the ∣Vcs∣|V_{cs}| is extracted to be 0.964Β±0.004Β±0.0190.964\pm0.004\pm0.019 where the first error is experimental and the second theoretical. Alternatively, the f+K(0)f_+^K(0) is extracted to be 0.7377Β±0.003Β±0.0000.7377\pm0.003\pm0.000 by taking the ∣Vcs∣|V_{cs}| as the value from the global fit with the unitarity constraint of the CKM matrix. Moreover, using the obtained form factors by Nf=2+1+1N_f=2+1+1 lattice QCD, we re-analyze these measurements in the context of new physics. Constraints on scalar leptoquarks are obtained for different final states of semileptonic Dβ†’KD \rightarrow K decays

    Topological and Algebraic Properties of Chernoff Information between Gaussian Graphs

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    In this paper, we want to find out the determining factors of Chernoff information in distinguishing a set of Gaussian graphs. We find that Chernoff information of two Gaussian graphs can be determined by the generalized eigenvalues of their covariance matrices. We find that the unit generalized eigenvalue doesn't affect Chernoff information and its corresponding dimension doesn't provide information for classification purpose. In addition, we can provide a partial ordering using Chernoff information between a series of Gaussian trees connected by independent grafting operations. With the relationship between generalized eigenvalues and Chernoff information, we can do optimal linear dimension reduction with least loss of information for classification.Comment: Submitted to Allerton2018, and this version contains proofs of the propositions in the pape
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