相关论文: Gluon Condensate from Superconvergent QCD Sum Rule

We calculate the $O(\alpha_s)$ and $O(\alpha_s^2)$ gluon radiative corrections to the QCD sum rule for the first Gegenbauer moment $a_1^K$ of the kaon light-cone distribution amplitude. The NNL0 accuracy is achieved for the perturbative…

The nucleon's tensor charges (isovector $g^v_T={\delta}u-{\delta}d$ and isoscalar $g^s_T={\delta}u+{\delta}d$) are calculated using the QCD sum rules in the presence of an external tensor field. In addition to the standard quark and gluon…

The B-decay constant $f_B$ is an important component for studying $B$-meson decays, which can be studied through QCD sum rules. We make a detailed discussion on $f_B$ from two sum rules, i.e. sum rules I and II, which are derived from the…

The paper presents the short review of our to-day knowledge of vacuum condensates in QCD. The condensates are defined as vacuum averages of the operators which arise due to nonperturbative effects. The important role of condensates in…

Gluons may converge to a stable state at a critical momentum in hadrons. This gluon condensation is predicted by a nonlinear QCD evolution equation. We review the understanding of the gluon condensation and present a clear physical picture…

We present a new calculation of the first Gegenbauer moment $a_1^K$ of the kaon light-cone distribution amplitude. This moment is determined by the difference between the average momenta of strange and nonstrange valence quarks in the kaon.…

We compute the quark and gluon condensates in $QCD$ with $N$ colors and $N_f$ flavors based on the renormalization group equations and on the knowledge of a single scale $\Lambda_{QCD}$. For $N=3$ and $N_f=3$ our findings are in the good…

The modern status of basic low energy QCD parameters is reviewed. It is demonstrated, that the recent data allows one to determine the light quark mass ratios with an accuracy 10-15%. The general analysis of vacuum condensates in QCD is…

We employ renormalization group (RG) summation techniques to obtain portions of Laplace QCD sum rules for scalar gluon currents beyond the order to which they have been explicitly calculated. The first two of these sum rules are considered…

The gluon condensation in the proton as a dynamical model is used to treat a series of unsolved puzzles in sub-TeV gamma ray spectra, they include the broken power-law of blazar's radiation, the hardening confusion of 1ES 1426+428, Mkn 501,…

We give the hyperasymptotic expansion of the plaquette with a precision that includes the terminant associated to the leading renormalon. Subleading effects are also considered. The perturbative series is regulated using the principal value…

We extract (for the first time) the ratio of the gluon condensate < g^3f_{abc}G^3 >/< alpha_s G^2 > expressed in terms of the liquid instanton radius rho_c from charmonium moments sum rules by examining the effects of < alpha_s G^2 > in the…

We re-examine the estimate of $\als$ and of the QCD condensates from $e^+e^-\rar I=1$ hadrons data. We conclude that $e^+e^-$ at low energies gives a value of $\Lambda$ compatible with the one from LEP and from tau inclusive decay. Using a…

It has been suggested recently to study the dynamics of a gravitating gluon condensate q in the context of a spatially flat Friedmann-Robertson-Walker universe. The expansion of the Universe (or, more generally, the presence of a…

Charmonium sum rules for pseudoscalar 0^{-+} state eta_c(1S) are analyzed within perturbative QCD and Operator Product Expansion. The perturbative part of the pseudoscalar correlator is considered at alpha_s^2 order and the contribution of…

In previous work, q-theory was introduced to describe the gravitating macroscopic behavior of a conserved microscopic variable q. In this article, the gluon condensate of quantum chromodynamics is considered in terms of q-theory. The…

After a short description of the currents coming from the known conservation laws in classical physics, we look at some further cases which arise after quantization in relation to quantum chromodynamics (QCD) at finite temperature. In these…

The precision measurement of the hyperfine splitting $\Delta_{\rm HF} (1P, c\bar c)=M_{\rm cog} (\chi_{cJ}) - M(h_c) = -0.5 \pm 0.4$ MeV in the Fermilab--E835 experiment allows to determine the gluonic condensate $G_2$ with high accuracy if…

We calculate the coefficients of the dimension-8 quark and gluon condensates in the current-current correlator of $1^{-+}$ light hybrid current $g\bar{q}(x)\gamma_{\nu}iG_{\mu\nu}(x)q{(x)}$. With inclusion of these higher-power corrections…

QCD sum rules for the nucleon are considered in complex q^2 plane with inclusion of the radiative corrections of the order alpha_s. It is shown that the radiative corrections affect mainly the residue lambda^2 of the nucleon pole. Their…