4,657 research outputs found

    Gell-Mann--Okubo Mass Formula for an SU(4) Meson Hexadecuplet

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    Using a linear mass spectrum of an SU(4)SU(4) meson hexadecuplet, we derive the Gell-Mann--Okubo mass formula for the charmed mesons, in good agreement with experiment. Possible generalization of this method to a higher symmetry group is briefly discussed.Comment: 11 pages, LaTe

    Review of Reactor Antineutrino Experiments

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    As discussed elsewhere, the measurement of a non-zero value for θ13\theta_{13} would open up a wide range of possibilities to explore CP-violation and the mass hierarchy. Experimental methods to measure currently the unknown mixing angle θ13\theta_{13} include accelerator searches for the νe\nu_{e} appearance and precise measurements of reactor antineutrino disappearance. The reactor antineutrino experiments are designed to search for a non-vanishing mixing angle θ13\theta_{13} with unprecedented sensitivity. This document describes current reactor antineutrino experiments and synergy between accelerator searches for the νe\nu_{e} appearance and precise measurements of reactor antineutrino disappearance.Comment: 8 pages, 2 figures, Review talk given at NuFact 2011, XIIIth InternationalWorkshop on Neutrino Factories, Super beams and Beta beams, CERN/UNIGE, Geneva, Switzerland, August 1-6, 201

    Multi-label classification using ensembles of pruned sets

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    This paper presents a Pruned Sets method (PS) for multi-label classification. It is centred on the concept of treating sets of labels as single labels. This allows the classification process to inherently take into account correlations between labels. By pruning these sets, PS focuses only on the most important correlations, which reduces complexity and improves accuracy. By combining pruned sets in an ensemble scheme (EPS), new label sets can be formed to adapt to irregular or complex data. The results from experimental evaluation on a variety of multi-label datasets show that [E]PS can achieve better performance and train much faster than other multi-label methods

    Updated Constraints on the Minimal Supergravity Model

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    Recently, refinements have been made on both the theoretical and experimental determinations of the i.) mass of the lightest Higgs scalar (m_h), ii.) relic density of cold dark matter in the universe (Omega_CDM h^2), iii.) branching fraction for radiative B decay BF(b \to s \gamma), iv.) muon anomalous magnetic moment (a_\mu), and v.) flavor violating decay B_s \to \mu^+\mu^-. Each of these quantities can be predicted in the MSSM, and each depends in a non-trivial way on the spectra of SUSY particles. In this paper, we present updated constraints from each of these quantities on the minimal supergravity (mSUGRA) model as embedded in the computer program ISAJET. The combination of constraints points to certain favored regions of model parameter space where collider and non-accelerator SUSY searches may be more focussed.Comment: 20 pages, 6 figures. Version published in JHE

    Standard Model Higgs boson production in association with a top anti-top pair at NLO with parton showering

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    We present predictions for the production cross section of a Standard Model Higgs boson in association with a top-antitop pair at next-to-leading order accuracy using matrix elements obtained from the HELAC-Oneloop package. The NLO prediction was interfaced to the PYTHIA and HERWIG shower Monte Carlo programs with the help of POWHEG-Box, allowing for decays of massive particles, showering and hadronization, thus leading to final results at the hadron level.Comment: 14 pages, 9 figure

    The Unseen Face of E-Business Project Development

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    The purpose of this paper is intent on identify and analyze the unseen factors of successful or failure of e-business project development. The IT managers must take into account both all costs involved in e-business development and all phases (analysis, design, testing, implementation, maintenance and operation) according to principle of project management for software/systems life cycle development. There are many solutions to exceed these factors of failure among could be counted outsourcing, a good project management, involvement of senior management, a real cost estimation etc.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej nauk

    QCD Multipole Expansion and Hadronic Transitions in Heavy Quarkonium Systems

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    We review the developments of QCD multipole expansion and its applications to hadronic transitions and some radiative decays of heavy quarkonia. Theoretical predictions are compsred with updated experimental results.Comment: 23 pages, 7 figures. Some typos corrected, and 3 references adde

    Proton polarizability contribution to the hydrogen hyperfine splitting

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    The contribution of the proton polarizability to the hydrogen hyperfine splitting is evaluated on the basis of modern experimental and theoretical results on the proton polarized structure functions. The value of this correction is equal to 1.4 ppm.Comment: 11 pages, LaTeX2.09, 7 figures, uses linedraw.sty, psfig.sty, epsf.st

    Texture of Yukawa coupling matrices in general two-Higgs-doublet model

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    We discuss possible parallel textures of the Yukawa coupling matrices in the generaltwo-Higgs-doublet model (2HDM). In those textures the flavor changing neutral currentsare naturally suppressed. Motivated by a phenomenologically successful texturewith four texture zeros in the standard model, we propose a predictive ansatz for the Yukawa coupling matrices with the same texture in the general 2HDM. Compared with the six texture-zero based ansatz proposed by Cheng and Sher, it is in a better agreement with the data of quark mixings and CP violation. The four texture-zero based ansatz predicts a different hierarchy in the Yukawa coupling matrix elements. As a consequence, in the lepton sector, the related Yukawa couplings are less constrained by the experimental upper bound of μeγ\mu\to e\gamma, which allows significantly larger predictions for other processes. The contributions from neutral scalar interactions to the lepton number violation decay modes 123\ell\to \ell_{1}\ell_{2}\ell_{3} are calculated in both ansatz. It is shown that the predictions from the four texture-zero based ansatz could be two order of magnitude greater than that from the six texture-zero based one. The branching ratio of μ3e\mu\to 3e and τ3μ\tau\to 3\mu can reach 7.5×10177.5 \times 10^{-17} and 1.3\tiems 10^{-10} respectively. The predicted ratio of Br(μ3e)/Br(τ3e)Br(\mu\to 3e)/Br(\tau\to 3e) is also larger and almost parameter independent. Those differences make the two ansatz to be easily distinguished by the future experiments.Comment: 12 pages, 2 figure

    JWST observations of stellar occultations by solar system bodies and rings

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    In this paper we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of solar system bodies and rings using stellar occultations. The strengths and weaknesses of the stellar occultation technique are evaluated in light of JWST's unique capabilities. We identify several possible JWST occultation events by minor bodies and rings, and evaluate their potential scientific value. These predictions depend critically on accurate a priori knowledge of the orbit of JWST near the Sun-Earth Lagrange-point 2 (L2). We also explore the possibility of serendipitous stellar occultations by very small minor bodies as a by-product of other JWST observing programs. Finally, to optimize the potential scientific return of stellar occultation observations, we identify several characteristics of JWST's orbit and instrumentation that should be taken into account during JWST's development.Comment: This paper is one of a series for a special issue on Solar System observations with JWST in PASP. Accepted 2-Oct-2015. Preprint 30 pages, 5 tables, 8 figure
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