43 research outputs found

    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 Q2≫m2Q^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 s→cs \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

    3-Loop Heavy Flavor Corrections in Deep-Inelastic Scattering with Two Heavy Quark Lines

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    We consider gluonic contributions to the heavy flavor Wilson coefficients at 3-loop order in QCD with two heavy quark lines in the asymptotic region Q2≫m1(2)2Q^2 \gg m_{1(2)}^2. Here we report on the complete result in the case of two equal masses m1=m2m_1 = m_2 for the massive operator matrix element Agg,Q(3)A_{gg,Q}^{(3)}, which contributes to the corresponding heavy flavor transition matrix element in the variable flavor number scheme. Nested finite binomial sums and iterated integrals over square-root valued alphabets emerge in the result for this quantity in NN and xx-space, respectively. We also present results for the case of two unequal masses for the flavor non-singlet OMEs and on the scalar integrals ic case of Agg,Q(3)A_{gg,Q}^{(3)}, which were calculated without a further approximation. The graphs can be expressed by finite nested binomial sums over generalized harmonic sums, the alphabet of which contains rational letters in the ratio η=m12/m22\eta = m_1^2/m_2^2.Comment: 10 pages LATEX, 1 Figure, Proceedings of Loops and Legs in Quantum Field Theory, Weimar April 201

    3-loop Massive O(TF2)O(T_F^2) Contributions to the DIS Operator Matrix Element AggA_{gg}

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    Contributions to heavy flavour transition matrix elements in the variable flavour number scheme are considered at 3-loop order. In particular a calculation of the diagrams with two equal masses that contribute to the massive operator matrix element Agg,Q(3)A_{gg,Q}^{(3)} is performed. In the Mellin space result one finds finite nested binomial sums. In xx-space these sums correspond to iterated integrals over an alphabet containing also square-root valued letters.Comment: 4 pages, Contribution to the Proceedings of QCD '14, Montpellier, July 201

    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 Q2≫m2Q^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

    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 Q2≫m2Q^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

    New Results on Massive 3-Loop Wilson Coefficients in Deep-Inelastic Scattering

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    We present recent results on newly calculated 2- and 3-loop contributions to the heavy quark parts of the structure functions in deep-inelastic scattering due to charm and bottom.Comment: Contribution to the Proc. of Loops and Legs 2016, PoS, in prin

    3-loop heavy flavor Wilson coefficients in deep-inelastic scattering

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    We present our most recent results on the calculation of the heavy flavor contributions to deep-inelastic scattering at 3-loop order in the large Q2Q^2 limit, where the heavy flavor Wilson coefficients are known to factorize into light flavor Wilson coefficients and massive operator matrix elements. We describe the different techniques employed for the calculation and show the results in the case of the heavy flavor non-singlet and pure singlet contributions to the structure function F2(x,Q2)F_2(x,Q^2).Comment: 4 pages Latex, 2 style files, 4 Figures, Contribution to the Proceedings of QCD '14, Montpellier, Jult 201

    3-Loop Corrections to the Heavy Flavor Wilson Coefficients in Deep-Inelastic Scattering

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    A survey is given on the status of 3-loop heavy flavor corrections to deep-inelastic structure functions at large enough virtualities Q2Q^2.Comment: 13 pages Latex, 8 Figures, Contribution to the Proceedings of EPS 2015 Wie

    The O(\alpha_s^3 T_F^2) Contributions to the Gluonic Operator Matrix Element

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    The O(αs3TF2CF(CA))O(\alpha_s^3 T_F^2 C_F (C_A)) contributions to the transition matrix element Agg,QA_{gg,Q} relevant for the variable flavor number scheme at 3--loop order are calculated. The corresponding graphs contain two massive fermion lines of equal mass leading to terms given by inverse binomially weighted sums beyond the usual harmonic sums. In xx-space two root-valued letters contribute in the iterated integrals in addition to those forming the harmonic polylogarithms. We outline technical details needed in the calculation of graphs of this type, which are as well of importance in the case of two different internal massive lines.Comment: 39 papges LATEX, 8 Figure

    Exact N3LO results for qq ′ → H + X

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    We compute the contribution to the total cross section for the inclusive production of a Standard Model Higgs boson induced by two quarks with different flavour in the initial state. Our calculation is exact in the Higgs boson mass and the partonic center-of-mass energy. We describe the reduction to master integrals, the construction of a canonical basis, and the solution of the corresponding differential equations. Our analytic result contains both Harmonic Polylogarithms and iterated integrals with additional letters in the alphabet. © 2015, The Author(s)
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