5,495 research outputs found

    Generalized μ−τ\mu-\tau reflection symmetry and leptonic CP violation

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    We propose a generalized μ−τ\mu-\tau reflection symmetry to constrain the lepton flavor mixing parameters. We obtain a new correlation between the atmospheric mixing angle θ23\theta_{23} and the "Dirac" CP violation phase δCP\delta_{\rm CP}. Only in a specific limit our proposed CP transformation reduces to standard μ−τ\mu-\tau reflection, for which θ23\theta_{23} and δCP\delta_{CP} are both maximal. The "Majorana" phases are predicted to lie at their CP-conserving values with important implications for the neutrinoless double beta decay rates. We also study the phenomenological implications of our scheme for present and future neutrino oscillation experiments including T2K, NOν\nuA and DUNE.Comment: 14 pages, 9 figures, latex, Final version to appear in Physics Letters

    Phase-field-crystal modeling of the (2x1)-(1x1) phase-transitions of Si(001) and Ge(001) surfaces

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    We propose a two-dimensional phase-field-crystal model for the (2×\times1)-(1×\times1) phase transitions of Si(001) and Ge(001) surfaces. The dimerization in the 2×\times1 phase is described with a phase-field-crystal variable which is determined by solving an evolution equation derived from the free energy. Simulated periodic arrays of dimerization variable is consistent with scanning-tunnelling-microscopy images of the two dimerized surfaces. Calculated temperature dependence of the dimerization parameter indicates that normal dimers and broken ones coexist between the temperatures describing the charactristic temperature width of the phase-transition, TLT_L and THT_H, and a first-order phase transition takes place at a temperature between them. The dimerization over the whole temperature is determined. These results are in agreement with experiment. This phase-field-crystal approach is applicable to phase-transitions of other reconstructed surface phases, especially semiconductor n×n\times1 reconstructed surface phases.Comment: 10 pages with 4 figures include

    Warped flavor symmetry predictions for neutrino physics

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    A realistic five-dimensional warped scenario with all standard model fields propagating in the bulk is proposed. Mass hierarchies would in principle be accounted for by judicious choices of the bulk mass parameters, while fermion mixing angles are restricted by a Δ(27)\Delta(27) flavor symmetry broken on the branes by flavon fields. The latter gives stringent predictions for the neutrino mixing parameters, and the Dirac CP violation phase, all described in terms of only two independent parameters at leading order. The scheme also gives an adequate CKM fit and should be testable within upcoming oscillation experiments.Comment: 19 pages, 2 figue

    Controllable selective exfoliation of high-quality graphene nanosheets and nanodots by ionic liquid assisted grinding

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    Bulk quantities of graphene nanosheets and nanodots have been selectively fabricated by mechanical grinding exfoliation of natural graphite in a small quantity of ionic liquids. The resulting graphene sheets and dots are solvent free with low levels of naturally absorbed oxygen, inherited from the starting graphite. The sheets are only two to five layers thick. The graphene nanodots have diameters in the range of 9-29 nm and heights in the range of 1-16 nm, which can be controlled by changing the processing time.Comment: * Corresponding authors: [email protected]; [email protected]

    Thermal radiation in non-static curved spacetimes: quantum mechanical path integrals and configuration space topology

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    A quantum mechanical path integral derivation is given of a thermal propagator in non-static Gui spacetime. The thermal nature of the propagator is understood in terms of homotopically non-trivial paths in the configuration space appropriate to tortoise coordinates. The connection to thermal emission from collapsing black holes is discussed.Comment: 20 pages, major revised version, 9 figures, new titl

    Probability density function of bubble size based reagent dosage predictive control for copper roughing flotation

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    As an effective measurement indicator of bubble stability, bubble size structure is believed to be closely related to flotation performance in copper roughing flotation. Moreover, reagent dosage has a very important influence on bubble size structure. In this paper, a novel reagent dosage predictive control method based on probability density function (PDF) of bubble size is proposed to implement the indices of roughing circuit. Firstly, the froth images captured in the copper roughing are segmented by using a two-pass watershed algorithm. In order to characterize bubble size structure with non-Gaussian feature, an entropy based B-spline estimator is hence investigated to depict the PDF of the bubble size. Since the weights of B-spline are interrelated and related to the reagent dosage, a multi-output least square support vector machine (MLS-SVM) is applied to depict a dynamic relationship between the weights and the reagent dosage. Finally, an entropy based optimization algorithm is proposed to determine reagent dosage in order to implement tracking control for the PDF of the output bubble size. Experimental results can show the effectiveness of the proposed method
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