Related papers: Renormalon contributions to \delta\rho
The impact of the resummed next-to-leading logarithmic small-$x$ contributions to the anomalous dimension $\gamma_{gg}$ is evaluated for the unpolarized parton densities and structure functions of the nucleon. These new terms diminish the…
Using the renormalon calculus, we study the asymptotic behavior of the perturbative expansion of the hard-scattering kernels entering the QCD factorization formula for the nonleptonic weak decays B->D M, where M is a light meson. In the…
A method of evaluation of spacelike QCD observables ${\cal D}(Q^2)$ is presented, motivated by the renormalon structure of these quantities.
In these lectures we give a concise introduction to the ideas of renormalon calculus in QED and QCD. We focus in particular on the example of the Adler D function of vacuum polarization, and on relations between perturbative renormalon…
We examine a variety of renormalization schemes in QCD based on its $3$-point vertices where the $\beta$-functions, gluon, ghost, quark and quark mass anomalous dimensions in each scheme do not depend on $\zeta_4$ or $\zeta_6$ in an…
I give a short review of the relation of infrared renormalons in QCD and higher twist effects, with the emphasis on possible applications. In particular, I present estimates of renormalon-induced uncertainties in deep inelastic sum rules…
The resummed expression for the quark form factor illustrates the fact that dimensional continuation provides a regularization not only for ultraviolet and infrared singularities of fixed order QCD amplitudes, but also for the Landau pole…
We fix exactly and uniquely the infrared structure of the full gluon propagator in QCD, not solving explicitly the corresponding dynamical equation of motion. By construction, this structure is an infinite sum over all possible severe…
For Non-Relativistic QCD the velocity renormalization group correlates the renormalization scales for ultrasoft, potential and soft degrees of freedom. Here we discuss the renormalization of operators by ultrasoft gluons. We show that…
The renormalization group is used to resum leading logarithmic contributions of the form alpha_s^{n+1} beta_0^n log^n (Delta/mu) to the gap equation appropriate for high density QCD. The scale dependence of the strong coupling constant…
Under certain assumptions and independent of the instantons, we show that the logarithm expansion of dimensional regularization in quantum field theory needs a nonperturbative completion to have a renormalization-group flow valid at all…
We calculate the leading-logarithmic and next-to-leading-logarithmic electroweak corrections to the charm-top-quark contribution to the effective $|\Delta S| = 2$ Lagrangian, relevant for the parameter $\epsilon_K$. We find that these…
The vacuum--polarization contributions of ${\cal O}(b^{n-1} \al_s^n)$ to the relation between the pole--mass $M$ of a quark and the \MS parameter $\mh (M)$ are evaluated by a straightforward method. They are found to approximate very well…
The full gluon propagator relevant for the description of the truly non-perturbative QCD dynamics, the so-called intrinsically non-perturbative gluon propagator has been derived in our previous work. It explicitly depends on the regularized…
The asymptotic structure of the QCD perturbative relation between the on-shell and $\overline{\rm{MS}}$ heavy quark masses is studied. We estimate the five and six-loop contributions to this relation by three different techniques. First,…
Infrared power corrections for Minkowskian QCD observables are analyzed in the framework of renormalon resummation, motivated by analogy with the skeleton expansion in QED and the BLM approach. Performing the ``massive gluon'' renormalon…
The explicit one-loop renormalizability of the gluon sector of QCD with Lorentz violation is demonstrated. The result is consistent with multiplicative renormalization as the required counter terms are consistent with a single re-scaling of…
We consider the structure of the leading ultra-violet (UV) renormalon singularity associated with the QCD vacuum polarization Adler D-function, in the approximation that only planar Feynman diagrams are retained. This ``planar…
The analysis of nonperturbative effects in high energy asymptotics of the electomagnetic quark form factor is presented. It is shown that the nonperturbative effects determine the initial value for the perturbative evolution of the quark…
This talk reviews progress in the (semi-) analytic calculations of the thermodynamics of the quark-gluon plasma. I shall explain how weak coupling techniques can allow us, through appropriate resummations, to deal with particular non…