1,415 research outputs found

    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

    Chiral phase transition in hadronic matter at non-zero baryon density

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    A qualitative analysis of the chiral phase transition in QCD at non--zero baryon density is performed. It is assumed that at zero baryonic density, ρ=0\rho=0, the temperature phase transition is of the second order and quark condesate η==<0dˉd0>\eta= \mid \mid =\mid< 0 \mid \bar{d}d\mid 0 >\mid may be taken as order parameter of phase transition. It is demonstrated, that the proportionality of baryon masses to quark condensate in the power 1/3, mB1/3m_B \sim \mid \mid^{1/3} is valid in the wide interval of quark condensate values. By supposing, that such specific dependence of baryon masses on quark condensate takes place up to phase transition point, it is shown, that at finite baryon density ρ\rho the phase transition becomes of the first order at the temperature T=Tph(ρ)T=T_{\mathrm{ph}}(\rho) for ρ>0\rho>0. At temperatures Tcont(ρ)>T>Tph(ρ)T_{\mathrm{cont}}(\rho) > T > T_{\mathrm{ph}}(\rho) there is a mixed phase consisting of the quark phase (stable) and the hadron phase (unstable). At the temperature T=Tcont(ρ)T = T_{\mathrm{cont}}(\rho) the system experiences a continuous transition to the pure chirally symmetric phase.Comment: 9 pages, 6 figures, Invited talk at 13-th International Seminar "Quarks-2004",Pushkinskie Gory, May 24-30, 2004, to be published in the Proceedings. v2. References are correcte
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