873 research outputs found

    The magnetic moments of 'Lambda_b' and 'Lambda_c' baryons in light cone QCD sum rules

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    Using the most general form of the interpolating currents of heavy baryons, the magnetic moments of heavy baryons "Lambda_Q (Q=b,c)" are calculated in framework of the light cone QCD sum rules. A comparison of our results on magnetic moments with the existing theoretical results calculated in various other frameworks are presented.Comment: 14 pp, 6 figures (postscript formatted), LaTex formatte

    Calculation of Chirality Violating Proton Structure Function h1_1(x) in QCD

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    The twist-two chirality violating proton structure function h1(x)h_1(x) measurable in the polarized Drell-Yan process is calculated by means of QCD sum rules at intermediate xx, 0.3<x<0.70.3 < x < 0.7 and Q2510GeV2Q^2 \approx 5-10 GeV^2.Comment: 12 pages + 6 figures , LaTeX, preprint LMU-01-94. a few additions to the text; the figures have been added as uuencoded fil

    On the Strength Calculation of the Rotating parts

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    AbstractThe existing solutions of differential equations of equilibrium of an infinitesimal element of the rotating parts of an isotropic elastic solid known as the Navier equilibrium equations are considered. Examples of the flat disk calculation by solving the differential equilibrium equations by the sweep method and the finite element method in the modern program “Autodesk Simulation Multiphysics” are represented; paradoxical changes of radial and hoop stresses are revealed. An original method of derivation formulas based only on the principle of d’Alembert to calculate radial and hoop stresses in parts that operate under centrifugal (inertial) forces is proposed. The solution for rotating disks of any profile that corrects unnatural classical solutions is obtained. Analysis of the obtained new formulas for calculating stresses shows that it is necessary to reject the concept of “equal-strength disk” because of the inability to provide the equality of the hoop and radial stress in all sections of the disk. A new method of the optimum strength disk profile calculation, which requires a restriction of outer radius disk, is suggested. In designing of optimum strength rotating parts is recommended to limit outer disk radius of where [σ] − the allowable stress, ρ − density of the disk material; ω − angular velocity of disk rotation

    Phenomenology of the Heavy Flavored spin 3/2 Baryons in Light Cone QCD

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    Motivated by the results of the recent experimental discoveries for charm and bottom baryons, the masses and magnetic moments of the heavy baryons with JP=3/2+J^P=3/2^+ containing a single heavy quark are studied within light cone QCD sum rules method. Our results on the masses of heavy baryons are in good agreement with predictions of other approaches, as well as with the existing experimental data.Comment: 12 Pages, 18 Figures and 3 Tables. Based on: arXiv:0807.3481v2 [hep-ph](Nucl.Phys.B808:137-154,2009). To be Published in the Proceeding of the International Conference on New Trends in High Energy Physics, 27 Sept.-4 Oct. 2008, Yalta, Crimea, Ukrain

    g_{rho sigma gamma} coupling constant in light cone QCD

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    The coupling constant g_{rho sigma gamma} is determined from light cone QCD sum rules. A comparison of our result with the ones existing in literature is presented.Comment: 7 pp, 2 figures (postscript formatted), LaTex formatte

    Twist-3 Distribute Amplitude of the Pion in QCD Sum Rules

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    We apply the background field method to calculate the moments of the pion two-particles twist-3 distribution amplitude (DA) ϕp(ξ)\phi_p(\xi) in QCD sum rules. In this paper,we do not use the equation of motion for the quarks inside the pion since they are not on shell and introduce a new parameter m0pm_0^p to be determined. We get the parameter m0p1.30GeVm_0^p\approx1.30GeV in this approach. If assuming the expansion of ϕp(ξ)\phi_p(\xi) in the series in Gegenbauer polynomials Cn1/2(ξ)C_n^{1/2}(\xi), one can obtain its approximate expression which can be determined by its first few moments.Comment: 12 pages, 3 figure

    The (Sigma_Q-Lambda_Q) transition magnetic moments in light cone QCD sum rules

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    Using the general form of (Sigma_Q) and (Lambda_Q) (Q=b or c) currents, (Sigma_Q-Lambda_Q) transition magnetic moments are calculated in framework of the light cone QCD sum rules method. In this approach nonperturbative effects are described by the photon wave functions and only two-particle photon wave functions are taken into account. Our predictions on transition magnetic moments are (mu_{Sigma_c Lambda_c} = - (1.5 pm 0.4) mu_N) and (mu_{Sigma_b Lambda_b} = - (1.6 pm 0.4) mu_N). A comparison of our results with the ones existing in the literature is given.Comment: 15 pp, 6 figures (postscript formatted), LaTex formatte

    Neutron EDM from Electric and Chromoelectric Dipole Moments of Quarks

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    Using QCD sum rules, we calculate the electric dipole moment of the neutron d_n induced by all CP violating operators up to dimension five. We find that the chromoelectric dipole moments of quarks \tilde d_i, including that of the strange quark, provide significant contributions comparable in magnitude to those induced by the quark electric dipole moments d_i. When the theta term is removed via the Peccei-Quinn symmetry, the strange quark contribution is also suppressed and d_n =(1\pm 0.5)[1.1e(\tilde d_d + 0.5\tilde d_u)+1.4(d_d-0.25d_u)].Comment: 4 pages, revtex, v2: missing overall factor of two reinstate

    Phase of the Wilson Line at High Temperature in the Standard Model

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    We compute the effective potential for the phase of the Wilson line at high temperature in the standard model to one loop order. Besides the trivial vacua, there are metastable states in the direction of U(1)U(1) hypercharge. Assuming that the universe starts out in such a metastable state at the Planck scale, it easily persists to the time of the electroweak phase transition, which then proceeds by an unusual mechanism. All remnants of the metastable state evaporate about the time of the QCDQCD phase transition.Comment: 4 pages in ReVTeX plus 1 figure; Columbia Univ. preprint CU-TP-63

    Radiative BBγB^{*}\to B\gamma and DDγD^{*}\to D\gamma decays in light cone QCD sum rules

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    The radiative decays B(D)B(D)γ B^{*} (D^{*})\rightarrow B(D) \gamma are investigated in the framework of light cone QCD sum rules. The transition amplitude and decay rates are estimated.It is shown that our results on branching ratios of D meson decays are in good agreement with the existing experimental data.Comment: 13 pages, Latex, 3 figure
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