3,221 research outputs found

    Pseudoscalar Meson Mixing in Effective Field Theory

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    We show that for any effective field theory of colorless meson fields, the mixing schemes of particle states and decay constants are not only related but also determined exclusively by the kinetic and mass Lagrangian densities. In the general case, these are bilinear in terms of the intrinsic fields and involve non-diagonal kinetic and mass matrices. By applying three consecutive steps this Lagrangian can be reduced into the standard quadratic form in terms of the physical fields. These steps are : (i) the diagonalization of the kinetic matrix, (ii) rescaling of the fields, and (iii) the diagonalization of the mass matrix. In case, where the dimensions of the non-diagonal kinetic and mass sub-matrices are respectively, k×kk\times k and n×nn\times n, this procedure leads to mixing schemes which involve [k(k−1)/2]+[n(n−1)/2][k(k-1)/2] + [n(n-1)/2] angles and kk field rescaling parameters. This observation holds true irrespective with the type of particle interactions presumed. The commonly used mixing schemes, correspond to a proper choice of the kinetic and mass matrices, and are derived as special cases. In particular, η\eta-ηâ€Č\eta ' mixing, requires one angle, if and only if, the kinetic term with the intrinsic fields has a quadratic form.Comment: REVTeX, 6 page

    Consistent SDNs through Network State Fuzzing

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    The conventional wisdom is that a software-defined network (SDN) operates under the premise that the logically centralized control plane has an accurate representation of the actual data plane state. Nevertheless, bugs, misconfigurations, faults or attacks can introduce inconsistencies that undermine correct operation. Previous work in this area, however, lacks a holistic methodology to tackle this problem and thus, addresses only certain parts of the problem. Yet, the consistency of the overall system is only as good as its least consistent part. Motivated by an analogy of network consistency checking with program testing, we propose to add active probe-based network state fuzzing to our consistency check repertoire. Hereby, our system, PAZZ, combines production traffic with active probes to continuously test if the actual forwarding path and decision elements (on the data plane) correspond to the expected ones (on the control plane). Our insight is that active traffic covers the inconsistency cases beyond the ones identified by passive traffic. PAZZ prototype was built and evaluated on topologies of varying scale and complexity. Our results show that PAZZ requires minimal network resources to detect persistent data plane faults through fuzzing and localize them quickly

    Hyperatlas: A New Framework for Image Federation

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    Hyperatlas is an open standard intended to facilitate the large-scale federation of image-based data. The subject of hyperatlas is the space of sphere-to-plane projection mappings (the FITS-WCS information), and the standard consists of coherent collections of these on which data can be resampled and thereby federated with other image data. We hope for a distributed effort that will produce a multi-faceted image atlas of the sky, made by federating many different surveys at different wavelengths and different times. We expect that hyperatlas-compliant imagery will be published and discovered through an International Virtual Observatory Alliance (IVOA) registry, and that grid-based services will emerge for the required resampling and mosaicking.Comment: Published in ADASS XIII proceeding

    Atlasmaker: A Grid-based Implementation of the Hyperatlas

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    The Atlasmaker project is using Grid technology, in combination with NVO interoperability, to create new knowledge resources in astronomy. The product is a multi-faceted, multi-dimensional, scientifically trusted image atlas of the sky, made by federating many different surveys at different wavelengths, times, resolutions, polarizations, etc. The Atlasmaker software does resampling and mosaicking of image collections, and is well-suited to operate with the Hyperatlas standard. Requests can be satisfied via on-demand computations or by accessing a data cache. Computed data is stored in a distributed virtual file system, such as the Storage Resource Broker (SRB). We expect these atlases to be a new and powerful paradigm for knowledge extraction in astronomy, as well as a magnificent way to build educational resources. The system is being incorporated into the data analysis pipeline of the Palomar-Quest synoptic survey, and is being used to generate all-sky atlases from the 2MASS, SDSS, and DPOSS surveys for joint object detection.Comment: Published in the Proceedings of ADASS XI

    SCET sum rules for B->P and B->V transition form factors

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    We investigate sum rules for heavy-to-light transition form factors at large recoil derived from correlation functions with interpolating currents for light pseudoscalar or vector fields in soft-collinear effective theory (SCET). We consider both, factorizable and non-factorizable contributions at leading power in the Lambda/m_b expansion and to first order in the strong coupling constant alpha_s, neglecting contributions from 3-particle distribution amplitudes in the B-meson. We pay particular attention to various sources of parametric and systematic uncertainties. We also discuss certain form factor ratios where part of the hadronic uncertainties related to the B-meson distribution amplitude and to logarithmically enhanced alpha_s corrections cancel.Comment: 27 pages, 19 figures, minor corrections, matches journal versio

    Semileptonic decays of pseudoscalar mesons to scalar "f_0" meson

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    The transition form factors of (D_s -> f_0 l nu), (D -> f_0 l nu) and (B_u -> f_0 l nu) decays are calculated in 3-point QCD sum rule method, assuming that "f_0" is a quark-antiquark state with a mixture of strange and light quarks. The branching ratios of these decays are calculated in terms of the mixing angle.Comment: 12 pages, 4 figures, LaTeX formatte

    The eta-photon transition form factor

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    The eta-photon transition form factor is evaluated in a formalism based on a phenomenological description at low values of the photon virtuality, and a QCD-based description at high photon virtualities, matching at a scale Q02Q_{0}^{2}. The high photon virtuality description makes use of a Distribution Amplitude calculated in the Nambu-Jona-Lasinio model with Pauli-Villars regularization at the matching scale Q02Q_{0}^{2}, and QCD evolution from Q02Q_{0}^{2} to higher values of Q2Q^{2}. A good description of the available data is obtained. The analysis indicates that the recent data from the BaBar collaboration on pion and eta transition form factor can be well reproduced, if a small contribution of twist three at the matching scale Q02Q_{0}^{2} is included.Comment: 14 pages, 3 figures, revised version, minor corrections, references added, conclusions unchanged. Accepted for publication in Phys. Rev.

    Decays of J/ψJ/\psi and ψâ€Č\psi^\prime into vector and pseudoscalar meson and the pseudoscalar glueball-qqˉq\bar{q} mixing

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    We introduce a parametrization scheme for J/ψ(ψâ€Č)→VPJ/\psi(\psi^\prime)\to VP where the effects of SU(3) flavor symmetry breaking and doubly OZI-rule violation (DOZI) can be parametrized by certain parameters with explicit physical interpretations. This scheme can be used to clarify the glueball-qqˉq\bar{q} mixing within the pseudoscalar mesons. We also include the contributions from the electromagnetic (EM) decays of J/ψJ/\psi and ψâ€Č\psi^\prime via J/ψ(ψâ€Č)→γ∗→VPJ/\psi(\psi^\prime)\to \gamma^*\to VP. Via study of the isospin violated channels, such as J/ψ(ψâ€Č)→ρηJ/\psi(\psi^\prime)\to \rho\eta, ρηâ€Č\rho\eta^\prime, ωπ0\omega\pi^0 and ϕπ0\phi\pi^0, reasonable constraints on the EM decay contributions are obtained. With the up-to-date experimental data for J/ψ(ψâ€Č)→VPJ/\psi(\psi^\prime)\to VP, J/ψ(ψâ€Č)→γPJ/\psi(\psi^\prime)\to \gamma P and P→γγP\to \gamma\gamma, etc, we arrive at a consistent description of the mentioned processes with a minimal set of parameters. As a consequence, we find that there exists an overall suppression of the ψâ€Č→3g\psi^\prime\to 3g form factors, which sheds some light on the long-standing "ρπ\rho\pi puzzle". By determining the glueball components inside the pseudoscalar η\eta and ηâ€Č\eta^\prime in three different glueball-qqˉq\bar{q} mixing schemes, we deduce that the lowest pseudoscalar glueball, if exists, has rather small qqˉq\bar{q} component, and it makes the η(1405)\eta(1405) a preferable candidate for 0−+0^{-+} glueball.Comment: Revised version to appear on J. Phys. G; An error in the code was corrected. There's slight change to the numerical results, while the conclusion is intac

    Mirror matter admixtures in K_L \to \gamma\gamma

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    Based on possible albeit tiny, admixtures of mirror matter in ordinary mesons we study the K_L \to \gamma\gamma transition. We find that this process can be described with a small SU(3) symmetry breaking of only 3%. We also determine the eta-eta' mixing angle and the pseudoscalar decay constants. The results for these parameters are consistent with some obtained in the literature. They favor two recent determinations; one based on two analytical constraints, and another one based on next-to-leading order power corrections
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