相关论文: Mixed quark-gluon condensate from instantons
In this article, we recalculate the contributions of all vacuum condensates up to dimension-6, in particular the one-loop corrections to the quark condensates $\alpha_s<\bar{q}q>$ and partial one-loop corrections to the four-quark…
The pion-baryon sigma terms and the strange-quark condensates of the octet and the decuplet baryons are calculated by employing the method of quantum chromodynamics (QCD) sum rules. We evaluate the vacuum-to-vacuum transition matrix…
We describe an approximate quantum mechanical picture of hadrons in Minkowski space in the context of a renormalization group procedure for effective particles (RGPEP) in a light-front Hamiltonian formulation of QCD. The picture suggests…
We present the two-loop virtual QCD corrections to the production of heavy quarks in gluon fusion. The results are exact in the limit when all kinematical invariants are large compared to the mass of the heavy quark up to terms suppressed…
Numerical and anaytical studies of the instanton liquid model have allowed the determination of many hadronic parameters during the last 13 years. Most part of this thesis is devoted to the extension of the analytical methods. The meson…
We present a QCD sum-rule determination of the heavy-quark kinetic energy inside a heavy meson, $-\lambda_1/2 m_Q$, which is consistent with the field-theory analog of the virial theorem. We obtain $-\lambda_1\approx (0.10\pm…
We have developed a phenomenological effective quantum-field theoretical model describing the "hadron gas" of the lightest pseudoscalar mesons, scalar {\sigma}-meson and {\sigma}-vacuum, i.e. the expectation value of the {\sigma}-field, at…
The estimations of the light quark mass differences, $m_d-m_u$, and the light quark condensate differences, $<\bar DD> - <\bar UU>$, are obtained in the framework of the \qm\ with QCD vacuum induced \q\ \ia . We consider long - wave…
Beyond the standard model, a static potential between quark pairs is obtained phenomenologically (QCD inspired), associated with the range of strong interaction, when the virtual exchange gluon squared momentum transfer has a periodicity…
The pion form factors of the QCD energy-momentum tensor (EMT) are studied in the instanton liquid model (ILM) of the QCD vacuum. In this approach the breaking of conformal symmetry is encoded in the form of stronger-than-Poisson…
We investigate the radiative break-up of a highly energetic quark or gluon in a high-temperature QCD plasma. Within an inertial range of momenta $T \ll \omega \ll E$, where $E$ denotes the energy of the original hard parton (jet) and $T$…
It is shown that an (anti-)self-dual homogeneous vacuum gluon field appears in a natural way within the problem of calculation of the QCD partition function in the form of Euclidean functional integral with periodic boundary conditions.…
Numerical and anaytical studies of the instanton liquid model have allowed the determination of many hadronic parameters during the last 13 years. Most part of this thesis is devoted to the extension of the analytical methods. The meson…
The flavour dependence of the mixed quark-gluon condensate is studied through the analysis of correlators of the hybrid current $a_{\mu}=g\bar s\gamma_{\rho}\gamma_5 G_{\rho\mu}d$. The flavour symmetry breaking for this type of condensates…
We present the first results from a study of the quark--gluon vertex function in the Landau gauge. The results are obtained for quenched QCD with an O(a)-improved Wilson fermion action, at beta=6.0. We discuss plans for further study,…
Field strength formulated Yang-Mills theory is confronted with the traditional formulation in terms of gauge fields. It is shown that both formulations yield the same semiclassics, in particular the same instanton physics. However, at the…
We calculate the potential between two static quarks in QCD using modified boundary conditions for the perturbative expansion. Through a change of the Feynman iepsilon prescription we effectively add a "sea" of gluons to the asymptotic…
We determine the phase diagram of QCD on the \mu-T plane for small to moderate chemical potentials. Two transition lines are defined with two quantities, the chiral condensate and the strange quark number susceptibility. The calculations…
Although the methods of calculation of power corrections in QCD sum rules are well known, algebraic complexity rapidly grows with the increase of vacuum condensates' dimensions. Currently, state-of-the-art calculations include dimension 7…
In this talk, I review the determinations of the QCD condensates and $\alpha_s$ within the SVZ expansion using the ratio of Laplace sum rule (LSR) and $\tau$-like moments in $e^+e^-\to I=1$ Hadrons and in $\tau\to \nu_\tau+$Hadrons…