19,213 research outputs found

    Understanding for flavor physics in the lepton sector

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    In this paper, we give a model for understanding flavor physics in the lepton sector--mass hierarchy among different generations and neutrino mixing pattern. The model is constructed in the framework of supersymmetry, with a family symmetry S4U(1)S4*U(1). There are two right-handed neutrinos introduced for seesaw mechanism, while some standard model(SM) gauge group singlet fields are included which transforms non-trivially under family symmetry. In the model, each order of contributions are suppressed by δ0.1\delta \sim 0.1 compared to the previous one. In order to reproduce the mass hierarchy, mτm_\tau and Δmatm2\sqrt{\Delta m_{atm}^2}, mμm_\mu and Δmsol2\sqrt{\Delta m_{sol}^2} are obtained at leading-order(LO) and next-to-leading-order(NLO) respectively, while electron can only get its mass through next-to-next-to-next-to-leading-order(NNNLO) contributions. For neutrino mixing angels, θ12,θ23,θ13\theta_{12}, \theta_{23}, \theta_{13} are 45,45,045^\circ, 45^\circ, 0 i.e. Bi-maximal mixing pattern as first approximation, while higher order contributions can make them consistent with experimental results. As corrections for θ12\theta_{12} and θ13\theta_{13} originate from the same contribution, there is a relation predicted for them sinθ13=1tanθ121+tanθ12\sin{\theta_{13}}=\displaystyle \frac{1-\tan{\theta_{12}}}{1+\tan{\theta_{12}}}. Besides, deviation from π4\displaystyle \frac{\pi}{4} for θ23\theta_{23} should have been as large as deviation from 0 for θ13\theta_{13} if it were not the former is suppressed by a factor 4 compared to the latter.Comment: version to appear in Phys. Rev.

    A Direct Method for Computing Higher Order Folds

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    We consider the computation of higher order fold or limit points of two parameter-dependent nonlinear problems. A direct method is proposed and an efficient implementation of the direct method is presented. Numerical results for the thermal ignition problem are given

    Response analysis of an automobile shipping container

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    The design and development of automobile shipping containers to reduce enroute damage are discussed. Vibration tests were conducted to determine the system structural integrity. A dynamic analysis was made using NASTRAN and the results of the test and the analysis are compared

    Bayesian Quantile Regression for Single-Index Models

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    Using an asymmetric Laplace distribution, which provides a mechanism for Bayesian inference of quantile regression models, we develop a fully Bayesian approach to fitting single-index models in conditional quantile regression. In this work, we use a Gaussian process prior for the unknown nonparametric link function and a Laplace distribution on the index vector, with the latter motivated by the recent popularity of the Bayesian lasso idea. We design a Markov chain Monte Carlo algorithm for posterior inference. Careful consideration of the singularity of the kernel matrix, and tractability of some of the full conditional distributions leads to a partially collapsed approach where the nonparametric link function is integrated out in some of the sampling steps. Our simulations demonstrate the superior performance of the Bayesian method versus the frequentist approach. The method is further illustrated by an application to the hurricane data.Comment: 26 pages, 8 figures, 10 table

    Challenge on the Astrophysical R-process Calculation with Nuclear Mass Models

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    Our understanding of the rapid neutron capture nucleosynthesis process in universe depends on the reliability of nuclear mass predictions. Initiated by the newly developed mass table in the relativistic mean field theory (RMF), in this paper the influence of mass models on the rr-process calculations is investigated assuming the same astrophysical conditions. The different model predictions on the so far unreachable nuclei lead to significant deviations in the calculated r-process abundances.Comment: 3 pages, 3 figure

    Casimir pistons with hybrid boundary conditions

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    The Casimir effect giving rise to an attractive or repulsive force between the configuration boundaries that confine the massless scalar field is reexamined for one to three-dimensional pistons in this paper. Especially, we consider Casimir pistons with hybrid boundary conditions, where the boundary condition on the piston is Neumann and those on other surfaces are Dirichlet. We show that the Casimir force on the piston is always repulsive, in contrast with the same problem where the boundary conditions are Dirichlet on all surfaces.Comment: 8 pages, 4 figures,references added, minor typos correcte
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