17,552 research outputs found

    Unstable manifolds and Schroedinger dynamics of Ginzburg-Landau vortices

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    The time evolution of several interacting Ginzburg-Landau vortices according to an equation of Schroedinger type is approximated by motion on a finite-dimensional manifold. That manifold is defined as an unstable manifold of an auxiliary dynamical system, namely the gradient flow of the Ginzburg-Landau energy functional. For two vortices the relevant unstable manifold is constructed numerically and the induced dynamics is computed. The resulting model provides a complete picture of the vortex motion for arbitrary vortex separation, including well-separated and nearly coincident vortices.Comment: 23 pages amslatex, 5 eps figures, minor typos correcte

    An investigation of the suitability of white rats for sub-orbital studies of behavior in a gravity field

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    Suitability of white rats for suborbital studies of behavior in gravity field

    The application of Floquet theory to the computation of small orbital perturbations over long time intervals using the Tschauner- Hempel equations

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    Calculation of path deviation of satellite from reference trajectory - perturbation theor

    Form Factors from Light-Cone Sum Rules with B-Meson Distribution Amplitudes

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    New sum rules for Bπ,KB\to \pi,K and Bρ,KB\to \rho,K^* form factors are derived from the correlation functions expanded near the light-cone in terms of B-meson distribution amplitudes. The contributions of quark-antiquark and quark-antiquark-gluon components in the B meson are taken into account. Models for the B-meson three-particle distribution amplitudes are suggested, based on QCD sum rules in HQET. Employing the new light-cone sum rules we calculate the form factors at small momentum transfers, including SU(3)flSU(3)_{fl} violation effects. The results agree with the predictions of the conventional light-cone sum rules.Comment: 32 pages, 7 figures, the discussion of numerical results extended, two references added, version to be published in Phys.Rev.

    B-Meson Distribution Amplitudes of Geometric Twist vs. Dynamical Twist

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    Two- and three-particle distribution amplitudes of heavy pseudoscalar mesons of well-defined geometric twist are introduced. They are obtained from appropriately parametrized vacuum-to-meson matrix elements by applying those twist projectors which determine the enclosed light-cone operators of definite geometric twist and, in addition, observing the heavy quark constraint. Comparing these distribution amplitudes with the conventional ones of dynamical twist we derive relations between them, partially being of Wandzura-Wilczek type; also sum rules of Burkhardt-Cottingham type are derived.The derivation is performed for the (double) Mellin moments and then re-summed to the non-local distribution amplitudes. Furthermore, a parametrization of vacuum-to-meson matrix elements for non-local operators off the light-cone in terms of distribution amplitudes accompanying independent kinematical structures is derived.Comment: 18 pages, Latex 2e, no figure

    Module production of the one-arm AFP 3D pixel tracker

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    The ATLAS Forward Proton (AFP) detector is designed to identify events in which one or two protons emerge intact from the LHC collisions. AFP will consist of a tracking detector, to measure the momentum of the protons, and a time of flight system to reduce the background from multiple proton-proton interactions. Following an extensive qualification period, 3D silicon pixel sensors were selected for the AFP tracker. The sensors were produced at CNM (Barcelona) during 2014. The tracker module assembly and quality control was performed at IFAE during 2015. The assembly of the first AFP arm and the following installation in the LHC tunnel took place in February 2016. This paper reviews the fabrication process of the AFP tracker focusing on the pixel modules.Comment: PIXEL 2016 proceedings; Submitted to JINS
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