We calculate a correction to the electromagnetic current induced by a heavy quark loop. The contribution of this correction to the vacuum polarization function appears at the O(αs) order of perturbation theory and has a qualitatively new feature – its absorptive part starts at zero energy in contrast to other contributions where the absorptive parts start at the two-particle threshold. Our resu...

Recent developments in Quantum Chromodynamics (QCD) are reviewed on three major topics where nonper-turbative gluon excitations of the QCD vacuum and the physical properties of the confining flux play a central role: (1) New lattice results on the spectrum and wave functions of heavy QQgluon molecules, known as heavy hybrids, will be discussed. (2) Recent advances on the glueball spectrum in la...

We start by presenting physical arguments for the impossibility of perturbative thermalization leading to (non-viscous) Bjorken hydrodynamic description of heavy ion collisions. These arguments are complimentary to our more formal argument presented in [1]. We argue that the success of hydrodynamic models in describing the quark-gluon system produced in heavy ion collisions could only be due to...

Light front (LF) Hamiltonian operators for effective particles in quantum field theory (QFT) provide a new path toward understanding of hadronic structure and interactions. The origin of new thrust is a far reaching simplification of the approach in comparison to the standard form of dynamics: boosts are kinematical, instantaneous potentials can exist on the front hyperplane without contradicti...

Abstract. Relativistic heavy ion collisions produce thousands of particles, and it is sometimes difficult to believe that these processes allow for a theoretical description directly in terms of the underlying theory – QCD. However once the parton densities are sufficiently large, an essential simplification occurs – the dynamics becomes semi– classical. As a result, a simple ab initio approach...