7,167 research outputs found

    QCD Sum Rules and the Determination of Leading Twist Non-Singlet Operator Matrix Elements

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    We use QCD sum rules to determine directly the leading-twist non-singlet operator matrix elements based on calculations of three-point correlator functions in configuration space. We find a different result from that obtained by integrating the structure functions' expressions obtained by Belyaev and Ioffe based on calculations of four-point correlators in momentum space. The origin of this discrepancy remains unclear.Comment: 9 pages, 5 figure

    The derivative of the topological susceptibility at zero momentum and an estimate of η\eta' mass in the chiral limit

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    The anomaly-anomaly correlator is studied using QCD sum rules. Using the matrix elements of anomaly between vacuum and pseudoscalars π,eta\pi, eta and η\eta', the derivative of correlator chi(0)chi'(0) is evaluated and found to be 1.82×103\approx 1.82 \times 10^{-3} GeV2^2. Assuming that χ(0)\chi'(0) has no significant dependence on quark masses, the mass of η\eta' in the chiral limit is found to be \approx723 MeV. The same calculation also yields for the singlet pseudoscalar decay constant in the chiral limit a value of 178\approx 178 MeV.Comment: LaTeX, 7 pages, 2 figures, uses cernrep.cls (included

    Comment on "Remark on the external-field method in QCD sum rules"

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    It is proved, that suggested by Jin modified formalism in the external-field method in QCD sum rules exactly coincides with the formalism used before. Therefore, unlike the claims of ref.1, this formalism cannot improve the predictability and reliability of external-field sum rule calculations in comparison with those, done by the standard approach. PACS number(s): 12.38.Lg, 11.55.HxComment: 5 pages, RevTe

    Quark distributions in QCD sum rules: unexpected features and paradoxes

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    Some very unusual features of the hadron structure functions, obtained in the generalized QCD sum rules, like the surprisingly strong difference between longitudinally and transversally polarized ρ\rho mesons structure functions and the strong suppression of the gluon sea in longitudinally polarized ρ\rho mesons are discussed. Also the problem of exact zero contribution of gluon condensates to pion and longitudinally polarized ρ\rho meson quark distributions is discussed.Comment: 9 pages, 5 fig

    Weak interaction contribution to the inclusive hadron-hadron scattering cross sections at high pTp_T

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    It is demonstrated that the strong power-like scaling violation in the transverse momentum distribution of inclusive hadron production, observed by CDF Collaboration in pˉp\bar{p}p collisions at Tevatron is caused by contribution of weak interaction. The contribution of weak interaction is increasing with energy at high energies.Comment: Talk presented at Gribov-80 Memorial Workshop, Trieste, May 26-28, 2010 and International seminar Quarks-2010, Colomna, June 6-12, 2010, 6 pages, 3 figures, it is accounted the weak boson formfactor, caused by strong interactio
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