70,313 research outputs found

    Analytical smoothing effect of solution for the boussinesq equations

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    In this paper, we study the analytical smoothing effect of Cauchy problem for the incompressible Boussinesq equations. Precisely, we use the Fourier method to prove that the Sobolev H 1-solution to the incompressible Boussinesq equations in periodic domain is analytic for any positive time. So the incompressible Boussinesq equation admet exactly same smoothing effect properties of incompressible Navier-Stokes equations

    Statistics Of The Burst Model At Super-critical Phase

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    We investigate the statistics of a model of type-I X-ray burst [Phys. Rev. E, {\bf 51}, 3045 (1995)] in its super-critical phase. The time evolution of the burnable clusters, places where fire can pass through, is studied using simple statistical arguments. We offer a simple picture for the time evolution of the percentage of space covered by burnable clusters. A relation between the time-average and the peak percentage of space covered by burnable clusters is also derived.Comment: 11 Pages in Revtex 3.0. Two figures available by sending request to [email protected]

    Long-term X-ray emission from Swift J1644+57

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    The X-ray emission from Swift J1644+57 is not steadily decreasing instead it shows multiple pulses with declining amplitudes. We model the pulses as reverse shocks from collisions between the late ejected shells and the externally shocked material, which is decelerated while sweeping the ambient medium. The peak of each pulse is taken as the maximum emission of each reverse shock. With a proper set of parameters, the envelope of peaks in the light curve as well as the spectrum can be modelled nicely.Comment: 6 pages, 2 figures, accepted for publication in MNRA

    Revisiting Charmless Hadronic B_{u,d} Decays in QCD Factorization

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    Within the framework of QCD factorization (QCDF), we consider two different types of power correction effects in order to resolve the CP puzzles and rate deficit problems with penguin-dominated two-body decays of B mesons and color-suppressed tree-dominated π0π0\pi^0\pi^0 and ρ0π0\rho^0\pi^0 modes: penguin annihilation and soft corrections to the color-suppressed tree amplitude. We emphasize that the electroweak penguin solution to the BKπB\to K\pi CP puzzle via New Physics is irrelevant for solving the CP and rate puzzles related to tree-dominated decays. While some channels e.g. Kπ+,Kρ0,π+π,ρ±πK^-\pi^+,K^-\rho^0,\pi^+\pi^-,\rho^\pm\pi^\mp need penguin annihilation to induce the correct magnitudes and signs for their CP violation, some other decays such as BKπ0,πη,KηB^-\to K^-\pi^0,\pi^-\eta, K^-\eta and Bˉ0Kˉ0η,π0π0\bar B^0\to \bar K^{*0}\eta,\pi^0\pi^0 require the presence of both power corrections to account for the measured CP asymmetries. In general, QCDF predictions for the branching fractions and direct CP asymmetries of BˉPP,VP,VV\bar B\to PP,VP,VV decays are in good agreement with experiment. The predictions of pQCD and soft-collinear effective theory are included for comparison.Comment: 51 pages, 1 figur
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