339 research outputs found

    The 3-Loop Non-Singlet Heavy Flavor Contributions to the Structure Function g_1(x,Q^2) at Large Momentum Transfer

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    We calculate the massive flavor non-singlet Wilson coefficient for the heavy flavor contributions to the polarized structure function g1(x,Q2)g_1(x,Q^2) in the asymptotic region Q2m2Q^2 \gg m^2 to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable NN and the momentum fraction xx, and derive heavy flavor corrections to the Bjorken sum-rule. Numerical results are presented for the charm quark contribution. Results on the structure function g2(x,Q2)g_2(x,Q^2) in the twist-2 approximation are also given.Comment: 29 pages, 8 Figure

    Heavy Flavor Wilson Coefficients in Deep-Inelastic Scattering: Recent Results

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    We present recent analytic results for the 3-loop corrections to the massive operator matrix element AQg(3)A_{Qg}^{(3)}for further color factors. These results have been obtained using the method of arbitrarily large moments. We also give an overview on the results which were obtained solving all difference and differential equations for the corresponding master integrals that factorize at first order.Comment: 11 pages Latex, To appear in the Proceedings of: QCDEV2017, JLAB, Newport News, VA, USA, May 22-26, 2017; Po

    The 3-Loop Pure Singlet Heavy Flavor Contributions to the Structure Function F2(x,Q2)F_2(x,Q^2) and the Anomalous Dimension

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    The pure singlet asymptotic heavy flavor corrections to 3-loop order for the deep-inelastic scattering structure function F2(x,Q2)F_2(x,Q^2) and the corresponding transition matrix element AQq(3),PSA_{Qq}^{(3), \sf PS} in the variable flavor number scheme are computed. In Mellin-NN space these inclusive quantities depend on generalized harmonic sums. We also recalculate the complete 3-loop pure singlet anomalous dimension for the first time. Numerical results for the Wilson coefficients, the operator matrix element and the contribution to the structure function F2(x,Q2)F_2(x,Q^2) are presented.Comment: 85 pages Latex, 14 Figures, 2 style file

    The O(\alpha_s^3) Heavy Flavor Contributions to the Charged Current Structure Function xF_3(x,Q^2) at Large Momentum Transfer

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    We calculate the massive Wilson coefficients for the heavy flavor contributions to the non-singlet charged current deep-inelastic scattering structure function xF3W+(x,Q2)+xF3W(x,Q2)xF_3^{W^+}(x,Q^2)+xF_3^{W^-}(x,Q^2) in the asymptotic region Q2m2Q^2 \gg m^2 to 3-loop order in Quantum Chromodynamics (QCD) at general values of the Mellin variable NN and the momentum fraction xx. Besides the heavy quark pair production also the single heavy flavor excitation scs \rightarrow c contributes. Numerical results are presented for the charm quark contributions and consequences on the Gross-Llewellyn Smith sum rule are discussed.Comment: 30 pages, 6 figures. arXiv admin note: text overlap with arXiv:1504.0821

    Calculating Three Loop Ladder and V-Topologies for Massive Operator Matrix Elements by Computer Algebra

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    Three loop ladder and VV-topology diagrams contributing to the massive operator matrix element AQgA_{Qg} are calculated. The corresponding objects can all be expressed in terms of nested sums and recurrences depending on the Mellin variable NN and the dimensional parameter ε\varepsilon. Given these representations, the desired Laurent series expansions in ε\varepsilon can be obtained with the help of our computer algebra toolbox. Here we rely on generalized hypergeometric functions and Mellin-Barnes representations, on difference ring algorithms for symbolic summation, on an optimized version of the multivariate Almkvist-Zeilberger algorithm for symbolic integration, and on new methods to calculate Laurent series solutions of coupled systems of differential equations. The solutions can be computed for general coefficient matrices directly for any basis also performing the expansion in the dimensional parameter in case it is expressible in terms of indefinite nested product-sum expressions. This structural result is based on new results of our difference ring theory. In the cases discussed we deal with iterative sum- and integral-solutions over general alphabets. The final results are expressed in terms of special sums, forming quasi-shuffle algebras, such as nested harmonic sums, generalized harmonic sums, and nested binomially weighted (cyclotomic) sums. Analytic continuations to complex values of NN are possible through the recursion relations obeyed by these quantities and their analytic asymptotic expansions. The latter lead to a host of new constants beyond the multiple zeta values, the infinite generalized harmonic and cyclotomic sums in the case of VV-topologies.Comment: 110 pages Latex, 4 Figure

    Characterization of variance in the high volume production of air bag control units

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.Includes bibliographical references (leaves 61-62).by Anthony von Behring.M.S

    The 3-Loop Non-Singlet Heavy Flavor Contributions and Anomalous Dimensions for the Structure Function F2(x,Q2)F_2(x,Q^2) and Transversity

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    We calculate the massive flavor non-singlet Wilson coefficient for the heavy flavor contributions to the structure function F2(x,Q2)F_2(x,Q^2) in the asymptotic region Q2m2Q^2 \gg m^2 and the associated operator matrix element Aqq,Q(3),NS(N)A_{qq,Q}^{(3), \rm NS}(N) to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable NN. This matrix element is associated to the vector current and axial vector current for the even and the odd moments NN, respectively. We also calculate the corresponding operator matrix elements for transversity, compute the contributions to the 3-loop anomalous dimensions to O(NF)O(N_F) and compare to results in the literature. The 3-loop matching of the flavor non-singlet distribution in the variable flavor number scheme is derived. All results can be expressed in terms of nested harmonic sums in NN space and harmonic polylogarithms in xx-space. Numerical results are presented for the non-singlet charm quark contribution to F2(x,Q2)F_2(x,Q^2).Comment: 82 pages, 3 style files, 33 Figure

    Emil von Behring (1854 - 1917) an Moritz Schmidt-Metzler (1838 - 1907) : Wiesbaden, 24. VIII, [18]99

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    Postkarte Emil von Behrings an Moritz Schmidt-Metzler mit Fragen zum Frankfurter Oberbürgermeister Franz Adickes

    Recent progress on the calculation of three-loop heavy flavor Wilson coefficients in deep-inelastic scattering

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    We report on our latest results in the calculation of the three-loop heavy flavor contributions to the Wilson coefficients in deep-inelastic scattering in the asymptotic region Q2m2Q^2 \gg m^2. We discuss the different methods used to compute the required operator matrix elements and the corresponding Feynman integrals. These methods very recently allowed us to obtain a series of new operator matrix elements and Wilson coefficients like the flavor non-singlet and pure singlet Wilson coefficients.Comment: 11 pages Latex, 2 Figures, Proc. of Loops and Legs in Quantum Field Theory, April 2014, Weimar, German
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