2,995 research outputs found

    The method of expansion of Feynman integrals

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    The method of expansion of integrals in external parameters is suggested. It is quite universal and works for Feynman integrals both in Euclidean and Minkowski regions of momenta.Comment: 6 pages, latex, no figure

    Higher derivative relativistic quantum gravity

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    Relativistic quantum gravity with the action including terms quadratic in the curvture tensor is analyzed. We derive new expressions for the corresponding Lagrangian and the graviton propagator within dimensional regularization. We argue that the considered model is a good candidate for the fundamental quantum theory of gravitation.Comment: 7 page

    Renormalizability of the massive Yang-Mills theory

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    It is shown that the massive Yang-Mills theory is on mass-shell renormalizable. Thus the Standard Model of electroweak interactions can be modified by removing terms with the scalar field from the Lagrangian in the unitary gauge. The resulting electroweak theory without the Higgs particle is on mass-shell renormalizable and unitary.Comment: 9 page

    Limits on Lorentz Violation from the Highest Energy Cosmic Rays

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    We place several new limits on Lorentz violating effects, which can modify particles' dispersion relations, by considering the highest energy cosmic rays observed. Since these are hadrons, this involves considering the partonic content of such cosmic rays. We get a number of bounds on differences in maximum propagation speeds, which are typically bounded at the 10^{-21} level, and on momentum dependent dispersion corrections of the form v = 1 +- p^2/Lambda^2, which typically bound Lambda > 10^{21} GeV, well above the Planck scale. For (CPT violating) dispersion correction of the form v = 1 + p/Lambda, the bounds are up to 15 orders of magnitude beyond the Planck scale.Comment: 24 pages, no figures. Added references, very slight changes. Version published in Physical Review

    Experimental investigation of pharmacokinetic properties and the accumulation of zinc when administrated nanoform of zinc hydroxide in a comparative aspect with zinc sulfate

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    The purpose of a preliminary assessment of the biological effect, a comparative study of nanoparticles using test cultures of bakery yeast, the results of which determined the level of inhibition, which was higher than 90%, compared with the figure for the zinc sulfate and the above 145% more compared to the zinc oxide. Investigation was performed on the pharmacokinetic characteristics of the 40 rabbits-males in comparison with that using zinc sulfate, in an enteral or intravenous administration at three dose levels: 10, 50 and 100 mg/k

    A multiloop improvement of non-singlet QCD evolution equations

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    An approach is elaborated for calculation of "all loop" contributions to the non-singlet evolution kernels from the diagrams with renormalon chain insertions. Closed expressions are obtained for sums of contributions to kernels P(z)P(z) for the DGLAP equation and V(x,y)V(x,y) for the "nonforward" ER-BL equation from these diagrams that dominate for a large value of b0b_0, the first β\beta-function coefficient. Calculations are performed in the covariant ξ\xi-gauge in a MS-like scheme. It is established that a special choice of the gauge parameter ξ=3\xi=-3 generalizes the standard "naive nonabelianization" approximation. The solutions are obtained to the ER-BL evolution equation (taken at the "all loop" improved kernel), which are in form similar to one-loop solutions. A consequence for QCD descriptions of hard processes and the benefits and incompleteness of the approach are briefly discussed.Comment: 13 pages, revtex, 2 figures are enclosed as eps-file, the text style and figures are corrected following version, accepted for publication to Phys. Rev.
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