Related papers: Perturbative QCD with Quark and Gluon Condensates
Quantum Chromodynamics on a lattice with Wilson fermions and a chirally twisted mass term for two degenerate quark flavours is considered in the framework of chiral perturbation theory. The pion masses and decay constants are calculated in…
The gluon and quark condensates and their temperature dependence are investigated within QCD premises. The input for the former is a gauge invariant $gg$ kernel made up of the direct (D), exchange (X) and contact(C) QCD interactions in the…
In this note, it is argued that the mass matrix for the six quarks can be generated in first approximation by introducing fermion condensates on the same lines as was done before for gluons, within the modified perturbative expansion for…
We introduced here the study of a QCD based on a complex group. Our aim is to show that a gauge theory with a complex symmetry develops some of the features required for the description of a confined phase. This theory leads to gluons with…
The structure of the quark propagator of $QCD$ in a confining background is not known. We make an Ansatz for it, as hinted by a particular mechanism for confinement, and analyze its implications in the meson and baryon correlators. We…
QCD, the theory of the strong interactions, involves quarks interacting with non-Abelian gluon fields. This theory has many features that are difficult to impossible to see in conventional diagrammatic perturbation theory. This includes…
We investigate the phase structure of QCD at finite temperature and chemical potential by solving a coupled set of truncated Dyson-Schwinger equations for the quark and gluon propagator. In contrast to previous calculations we take into…
None of the asymptotic states commonly used in perturbative QCD are gauge invariant. A similar statement could be made about QED, but in QED one can construct gauge invariant "dressed" states (with Dirac electrons) that are unitarily…
We study an extended QCD model in (1+1) dimensions obtained from QCD in 4D by compactifying two spatial dimensions and projecting onto the zero-mode subspace. We work out this model in the large $N_c$ limit and using light cone gauge but…
We propose to calculate the gluon condensate in lattice QCD in an indirect way by extracting it from the correlator of hadronic currents of heavy quarks. Moments (derivatives with respect to momentum at vanishing momentum) of the vector and…
Using effective potential approach for composite operators we have formulated quantum model of the QCD vacuum. It is based on the existence and importance of the nonperturbative $q^{-4}$, topologically nontrivial excitations of the gluon…
By introducing auxiliary fields, which by their quantum numbers vanish in perturbation theory, we relate the dynamical perturbation theory of Pagels and Stokar and a successful gauged nonlocal constituent quark model to $U(N)$ gauge theory…
We have investigated a closed set of equations for the quark propagator, which has been obtained earlier within a new, nonperturbative approach to two-dimencional covariant gauge QCD. It is shown that this theory implies quark confinement…
In QCD both the quark and ghost propagators are important for governing the non-perturbative dynamics of the theory. It turns out that the dynamical properties of the quark and ghost fields impose non-perturbative constraints on the…
We determine several quantities in quenched lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with Wilson gauge action at $ \beta = 6.0 $ on the $ 16^3 \times 32 $ lattice, we compute quenched quark propagators…
Equal time, point to point correlation functions for spatially separated meson currents are calculated with respect to a variational construct for the ground state of QCD. Given such an ansatz we make no further approximations in the…
Basic chiral QCD parameters (the pion decay constant, the quark and gluon condensates, the dynamically generated quark mass, etc) as well as the vacuum energy density have been calculated from first principles within a recently proposed…
It has long been known that the gluon propagator in Landau-gauge QCD exhibits a mass gap; and its emergence has been ascribed to the action of the Schwinger mechanism in the gauge sector of QCD. In the present work, we relate this property…
We use both old and new theoretical developments in QCD dispersion relation constraints on the scalar form factor in the decay K --> \pi l \nu_l to obtain constraints on the strange quark mass. The perturbative QCD side of the calculation…
We demonstrate that QCD gluon amplitudes can be used to construct a Lagrangian for gravity. This procedure makes use of perturbative `squaring' relations between gravity and gauge theory that follow from string theory. We explicitly carry…