Related papers: QCD at complex coupling, large order in perturbati…
The relevance of higher order cumulants of conserved charges for the analysis of freeze-out and critical conditions in heavy ion collisions at LHC and RHIC is discussed. Using properties of $O(4)$ scaling functions, the generic structure of…
We consider extensions of the soft-gluon effective coupling that generalize the Catani--Marchesini--Webber (CMW) coupling in the context of soft-gluon resummation beyond the next-to-leading logarithmic accuracy. Starting from the…
Numerical Stochastic Perturbation Theory (NSPT) enables very high order computations in Lattice Gauge Theories. We report on the determination of the gluon condensate from lattice QCD measurements of the basic plaquette. This is a long…
A particular initial state for the construction of the perturbative expansion of QCD is investigated. It is formed as a coherent superposition of zero momentum gluon pairs and shows Lorentz as well as global SU(3) symmetries. It follows…
A particular initial state for the construction of a perturbative QCD expansion is investigated. It is formed as a coherent superposition of zero momentum gluon pairs and shows Lorentz as well as global $SU(3)$ symmetries. The general form…
We discuss upon recent progress in our knowledge of the large order behavior in perturbation theory of the pole mass and the singlet static potential. We also discuss about the renormalon subtracted scheme, a matching scheme between QCD and…
We present a new perspective on the nature of quark and gluon condensates in quantum chromodynamics. We suggest that the spatial support of QCD condensates is restricted to the interiors of hadrons, since these condensates arise due to the…
Recently-developed variational perturbation expansions converge exponentially fast for positive coupling constants. They do not, however, possess the correct left-hand cut in the complex coupling constant plane, implying a wrong large-order…
After reviewing basic facts about large-order behaviour of perturbation expansions in various fields of physics, I consider several alternatives to the Borel summation method and discuss their relevance to different physical situations.…
QCD sum rules for the nucleon are considered in complex q^2 plane with inclusion of the radiative corrections of the order alpha_s. It is shown that the radiative corrections affect mainly the residue lambda^2 of the nucleon pole. Their…
Recent progress in understanding general properties of high energy scattering near the unitarity limit, where high density gluon components of the wavefunction are dominant, is reviewed. The similarity of the QCD problem and that of…
We discuss the predictions of perturbative QCD for angular flows of final state particles in two and three jet events including their cms energy and jet resolution (y_{cut}) dependence. The simple analytical formulae for gluon…
An analytic ghost-free model for the QCD running coupling $\alpha(Q^2)$ is proposed. It is constructed from a more general approach we developed particularly for investigating physical observables of the type $F(Q^2)$ in regions that are…
We determine the non-perturbative gluon condensate of four-dimensional SU(3) gauge theory in a model independent way. This is achieved by carefully subtracting high order perturbation theory results from non-perturbative lattice QCD…
The pressure of QCD admits at high temperatures a factorization into purely perturbative contributions from "hard" thermal momenta, and slowly convergent as well as non-perturbative contributions from "soft" thermal momenta. The latter can…
Using perturbation theory in the strong coupling regime, that is, the dual Dyson series, and renormalization group techniques to re-sum secular terms, we obtain the perturbation series of the two-level system driven by a sinusoidal field…
The existence in the physical QCD vacuum of nonzero gluon condensates, such as $<g^2F^2>$, requires dominance of gluon fields with finite mean action density. This naturally allows any real number value for the unit ``topological charge''…
We compare MC calculations of the density of states in SU(2) pure gauge theory with the weak and strong coupling expansions. Surprisingly, the range of validity of the two approximations overlap significantly, however the large order…
We study in detail the exchange of a Coulomb (Glauber) gluon in the first few orders of QCD perturbation theory in order to shed light on their accounting to all orders. We find an elegant cancellation of graphs that imposes a precise…
We propose a hypothesis on the detailed structure for the representation of the conformal symmetry breaking term in the basic Crewther relation generalized in the perturbation theory framework in QCD renormalized in the ${\rm \bar{MS}}$…