6,257 research outputs found

    Mixing Angle of Hadrons in QCD: A New View

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    A new method for calculation of the mixing angle between the hadrons within QCD sum rules is proposed. In this method, the mixing is expressed in terms of quark and gluon degrees of freedom. As an application, the detailed calculation of the mixing angle between heavy cascade baryons Xi_Q and Xi_Q', Q=c,~b is presented and it is found that the mixing angle between Xi_b (Xi_c) and Xi_b' (Xi_c') is given by theta_b = 6.4^\circ \pm 1.8 ^\circ (theta_c = 5.5^\circ \pm 1.8^\circ).Comment: 10 pages, 4 figures, 1 table, Changes in the text onl

    Double-lepton polarizations in (B -> l^+ l^- gamma) decay

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    Double-lepton polarization asymmetries in the (B -> l^+ l^- gamma) decay are calculated using the most general, model independent form of the effective Hamiltonian including all possible forms of the interaction. The dependencies of the asymmetries on new Wilson coefficients are investigated. The detectability the averaged double-lepton polarization asymmetries at LHC is also discussed.Comment: 20 pages, 7 PostScript figures, LaTeX formatte

    Light vector meson octet-decuplet baryon vertices in QCD

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    The strong coupling constants between light vector mesons and octet-decuplet baryons are calculated in framework of the light cone QCD sum rules, taking into account SU(3) flavor symmetry breaking effects. It is shown that all strong coupling constants can be represented in terms of a single universal function. Size of the SU(3) symmetry breaking effects are estimated.Comment: 27 pages, 6 figures, LaTeX formatte

    Vector meson dominance and radiative decays of heavy spin-3/2 baryons to heavy spin--1/2 baryons

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    Using the calculated values of the strong coupling constants of the heavy sextet spin-3/2 baryons to sextet and antitriplet heavy spin-1/2 baryons with light mesons within the light cone QCD sum rules method, and vector meson dominance assumption, the radiative decay widths are calculated. These widths are compared with the "direct" radiative decay widths predicted in the framework of the light cone QCD sum rules.Comment: 8 pages, no figures, LaTeX formatte

    Unitary Structure of the QCD Sum Rules and KYN and KY\Xi Couplings

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    New relations between QCD Borel sum rules for strong coupling constants of K-mesons to baryons are derived. It is shown that starting from the sum rule for the coupling constants gπΣΣg_{\pi\Sigma\Sigma} and gπΣΛg_{\pi\Sigma\Lambda} it is straightforward to obtain corresponding sum rules for the gKYNg_{K Y N}, gKYΞg_{K Y \Xi} couplings, Y=Σ,ΛY=\Sigma,\Lambda.Comment: 7 pages, 2 tables, International Workshop on Quantum Chromodynamics:Theory and Experiment, QCD@Work-2005, Coversano(Bari, Italy), 16-20 June, 200

    Magnetic Moments of Heavy ΞQ\Xi_{Q} Baryons in Light Cone QCD Sum Rules

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    The magnetic moments of heavy ΞQ\Xi_{Q} baryons containing a single charm or bottom quark are calculated in the framework of light cone QCD sum rules method. A comparison of our results with the predictions of the quark models is presented.Comment: 26 Pages, 8 Figures and 1 Tabl

    Electromagnetic form factors of the (rho) meson in light cone QCD sum rules

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    We investigate the electromagnetic form factors of the (rho) meson in light cone QCD sum rules. We find that the ratio of the magnetic and charge form factors is larger than two at all values of Q^2, (Q^2 >= 0.5 GeV^2). The values of the individual form factors at fixed values of Q^2 predicted by the light cone QCD sum rules are quite different compared to the results of other approaches. These results can be checked in future, when more precise data on (rho) meson form factors is available.Comment: 12 pages, 6 figures, LaTeX formatte

    Scalar form factor of the nucleon and nucleon--scalar meson coupling constant in QCD

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    Scalar form factor of the nucleon is calculated in the framework of light cone QCD sum rules, using the most general form of the baryon current. Using the result on scalar form factor of the nucleon, the nucleon-scalar "sigma" and "a_0" meson coupling constants are estimated. Our results on these couplings are in good agreement with the prediction of the external field QCD sum rules method.Comment: 20 pages, 12 figures, LaTeX formatte

    Broadband probing magnetization dynamics of the coupled vortex state permalloy layers in nanopillars

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    Broadband magnetization response of coupled vortex state magnetic dots in layered nanopillars was explored as a function of in-plane magnetic field and interlayer separation. For dipolarly coupled circular Py(25 nm)/Cu(20 nm)/Py(25 nm) nanopillars of 600 nm diameter, a small in-plane field splits the eigenfrequencies of azimuthal spin wave modes inducing an abrupt transition between in-phase and out-of-phase kinds of the low-lying coupled spin wave modes. The critical field for this splitting is determined by antiparallel chiralities of the vortices in the layers. Qualitatively similar (although more gradual) changes occur also in the exchange coupled Py(25 nm)/Cu(1 nm)/Py(25 nm) tri-layer nanopillars. These findings are in qualitative agreement with micromagnetic dynamic simulations
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