We elucidate constraints imposed by confinement and dynamical chiral symmetry breaking on the infrared behaviour of the dressed-quark and -gluon propagators, and dressed-quark-gluon vertex. In covariant gauges the dressing of the gluon propagator is completely specified by P(k2) := 1/[1+Π(k2)], where Π(k2) is the vacuum polarisation. In the absence of particle-like singularities in the dressed-...

In this talk we discuss gluon radiation in top production and decay. After reviewing results for hadron colliders we consider soft gluon radiation at lepton colliders and present gluon distributions that are potentially sensitive to production-decay interference effects.

A calculation of thermal gluon decay shows that this process contributes significantly to strangeness production in a quark-gluon plasma. Our analysis does not support recent claims that this is the dominant process. In our calculations we take into account the resummed form of the transverse and longitudinal parts of the gluon propagator following the Braaten-Pisarski method. Our results are s...

We study evolution of colour gluon states in isolated QCD jet and prove the possibility of existence of the gluon squeezed states at the nonperturbative stage of the jet evolution. Angular and rapidity dependencies of gluon squeezed second correlation function are studied. We demonstrate that these new gluon states can have both sub-Poissonian and super-Poissonian statistics corresponding to an...

We review the status of the calculation of the time-like splitting functions for the evolution of fragmentation functions to the next-to-next-to-leading order in perturbative QCD. By employing relations between space-like and time-like deep-inelastic processes, all quark-quark and the gluon-gluon time-like splitting functions have been obtained to three loops. The corresponding quantities for t...

We address the problem of Gribov copies in lattice QCD. The gluon propagator is computed, in the Landau gauge, using 302 (β = 5.8) 12 configurations gauge fixed to different copies. The results of the simulation shows that: i) the effect of Gribov copies is small (less than 10%); ii) Gribov copies change essentially the lowest momenta components (q < 2.6 GeV); iii) within the statistical accura...

Massless diquark jet and gluon jet productions at large transverse momentum in the coherent diffractive processes at hadron colliders are studied in the two-gluon exchange parametrization of the Pomeron model. We use the helicity amplitude method to calculate the cross section formulas. We find that for the light quark jet and gluon jet production the diffractive process is related to the diffe...