Related papers: Gluon Mass from Instantons
In this contribution we extend our unquenched computation of the Landau gauge gluon and ghost propagators in lattice QCD at non-zero temperature. The study was aimed at providing input for investigations employing continuum functional…
We discuss a method to extract the K\"all\'en-Lehmann spectral density of a particle (be it elementary or bound state) propagator and apply it to compute gluon spectral densities from lattice data. Furthermore, we also consider the…
Scaling of the Landau gauge gluon propagator calculated at beta=6.0 and at beta=6.2 is demonstrated. A variety of functional forms for the gluon propagator calculated on a large (32^3x64) lattice at beta=6.0 are investigated.
The gauge-invariant generation of a dynamical, momentum-dependent gluon mass is intimately connected with the presence of non-perturbative massless poles in the vertices of the theory, which trigger the well-known Schwinger mechanism. In…
Propagators of the diagonal and the off-diagonal gluons are studied numerically in the Maximal Abelian gauge of SU(2) lattice gauge theory. It is found that in the infrared region the propagator of the diagonal gluon is strongly enhanced in…
In the d=3 gluon mass problem in pure-glue non-Abelian $SU(N)$ gauge theory we pay particular attention to the observed (in Landau gauge) violation of positivity for the spectral function of the gluon propagator. This causes a large bulge…
The dynamically generated effective gluon mass is known to depend non-trivially on the momentum, decreasing sufficiently fast in the deep ultraviolet, in order for the renormalizability of QCD to be preserved. General arguments based on the…
We derive the form of the infrared gluon propagator by proving a mapping in the infrared of the quantum Yang-Mills and $\lambda\phi^4$ theories. The equivalence is complete at a classical level. But while at a quantum level, the…
We investigate gluon propagators and the effective mass of the gluon fields in the MA gauge with U(1)$_3 \times$ U(1)$_8$ Landau gauge fixing in SU(3) lattice QCD. The Monte Carlo simulation is performed on $16^4$ at $\beta$=5.7, 5.8 and…
We present the general derivation of the full non-perturbative equation that governs the momentum evolution of the dynamically generated gluon mass, in the Landau gauge. The entire construction hinges crucially on the inclusion of…
We present a novel analysis of the gluon gap equation, where its full nonlinear structure is duly taken into account. In particular, while in previous treatments the linearization of this homogeneous integral equation introduced an…
The charmonium sum rules for the axial-vector current are considered. The three-loop perturbative corrections, operators up to 8 dimension and perturbative corrections to the lowest dimension operator are accounted. The contribution of the…
Parton distribution functions for protons are devised in which a light gluino is included along with standard model quark, antiquark, and gluon constituents. A global analysis of a large set of hadronic scattering data provides empirical…
Assuming the gluon field is well approximated by instanton configurations we derive a light quarks determinant and calculate its contribution to the specific heavy quarks correlators -- namely, the heavy quark propagator and heavy…
Instanton effects and three-loop perturbative contributions are incorporated into QCD sum-rule analyses of pseudoscalar ($J^{PC}=0^{-+}$) gluonium. Gaussian sum-rules are shown to be superior to Laplace sum-rules in optimized predictions…
The influence of nonperturbative fields on instantons in quantum chromodynamics is studied. Nonperturbative vacuum is described in terms of nonlocal gauge invariant vacuum averages of gluon field strength.Effective action for instanton is…
The meson (pion and kaon) form factor is calculated in the perturbative framework with alternative forms for the running coupling constant and the gluon propagator in the infrared kinematic region. These modified forms are employed to test…
A one parameter, model confined-gluon propagator is employed in a phenomenological application of the Dyson-Schwinger and Bethe-Salpeter equations to the calculation of a range of $\pi$- and $\rho$-meson observables. Good agreement is…
The gravitational form factors (GFFs) of hadrons encode the matrix elements of the energy momentum tensor of QCD. These quantities describe how energy, spin, and various mechanical properties of hadrons are carried by their quark and gluon…
We consider pure glue QCD at beta=5.7, beta=6.0 and beta=6.3. We evaluate the gluon propagator both in time at zero 3-momentum and in momentum space. From the former quantity we obtain evidence for a dynamically generated effective mass,…