We study the properties of gluons in QCD in the maximally abelian (MA) gauge. In the MA gauge, the off-diagonal gluon behaves as the massive vector boson with the mass Moff ' 1.2 GeV, and therefore the off-diagonal gluon cannot carry the long-range interaction for r M−1 off ' 0.2 fm. The essence of the infrared abelian dominance in the MA gauge is physically explained with the generation of the...

Parton distribution functions in the nucleons have been obtained primarily through lepton-induced deep-inelastic scattering (DIS) experiments. One of the most important unresolved issues in our current knowledge of parton distributions is the role of gluons for describing the nucleon spin. While gluon polarization, ∆G(x), could in principle be deduced from the Q-evolution of the polarized struc...

We exhibit the method for obtaining non perturbative quark and gluonic vacuum condensates from a model truncation of QCD. The truncation allows for a phenomenological description of the quark-quark interaction in a framework which maintains all global symmetries of QCD and allows an 1 Nc expansion. Within this approach the functional integration over the gluon fields can be performed and theref...

A global color symmetry model (GCM) that is based upon an effective quark-quark interaction arises from the QCD partition function by formally integrating over the gluon fields and truncating the expansion in gluon n point functions after n = 2. 1 This model truncation respects all global symmetries of QCD, in particular chiral symmetry. What is lost is invariance under local color gauge transf...

The equation for two reggeized gluons in the vacuum channel is generalized to take into account the running QCD coupling constant on the basis of the bootstrap condition for gluon reggeization. Both the gluon trajectory as a function of momentum and the interaction as a function of distance grow like log log in the ultraviolet. The resulting equation depends on the confinement region. With a si...

We calculate shadowing using new data on the gluon density of the Pomeron recently measured with high precision at HERA. The calculations are made in a Glauber-Gribov framework and Pomeron tree-diagrams are summed up within a unitarity-conserving procedure. The total cross section of γA interaction is then found in a parameter-free description, employing gluon diffractive and inclusive distribu...

The QCD gauge field is modeled as an ensemble of statistically independent selfdual and antiselfdual regions. This model is motivated from instanton physics. The scale anomaly then allows to relate the topological susceptibility to the gluon condensate. With the help of Wittens formula for mη′ and an estimate of the suppression of the gluon condensate due to light quarks the mass of the η can b...

U A (1) symmetry breaking is studied by introducing the flavor mixing interaction proposed by Kobayashi, Maskawa and 't Hooft. Combining the one gluon exchange interaction , the rainbow like Schwinger–Dyson equation and the ladder like Bethe–Salpeter equation are derived. The anomalous PCAC relation in the framework of this approximation is considered. The masses of the pseudoscalar mesons π, η...