相关论文: Renormalons and Power Corrections

Power corrections to exclusive processes are usually calculated using models for twist-four distribution amplitudes (DA) which are based on the leading-order terms in the conformal expansion. In this work we develop a different approach…

It is shown that exact, amplitude-based resummation allows IR-improvement of the usual DGLAP theory. This results in a new set of kernels, parton distributions and attendant reduced cross sections, so that the QCD perturbative result for…

We review the physics of the ultraviolet renormalon. This mini-review is intended to be a sequel to the review by the same authors at the "QCD '96" conference last year (hep-ph/9610492).

Perturbative QCD (pQCD) running coupling a(Q^2) (=alpha_s(Q^2)/pi) is expected to get modified at low spacelike momenta 0 < Q^2 < 1 GeV^2 so that, instead of having unphysical (Landau) singularities it remains smooth and finite there, due…

Starting from the divergence pattern of perturbative quantum chromodynamics, we propose a novel, non-power series replacing the standard expansion in powers of the renormalized coupling constant $a$. The coefficients of the new expansion…

The renormalon calculus is used to calculate the terms of order $\beta_0^{n-1}\alpha_s^n$ in the perturbative expansions of the Wilson coefficients and hard-scattering kernels entering the QCD factorization formula for hadronic B-meson…

We consider non-perturbative effects at short distances in theories with confinement. The analysis is straightforward within the Abelian models in which the confinement arises on classical level. In all cases considered (compact U(1) in 3D…

I discuss collinear and infrared divergences in QCD cross sections with massless and massive final-state particles. I present the two-loop renormalization group evolution and resummation in terms of anomalous dimensions, and I show specific…

We discuss the ways of extracting a low energy scale of an underlying theory using high energy scattering data. Within an exactly solvable model of quantum mechanics we analyze a technique based on introduction of nonperturbative power…

I review the basics of perturbative QCD, including infrared divergences and safety, collinear and $k_T$ factorization theorems, and various evolution equations and resummation techniques for single- and double-logarithmic corrections. I…

Evolution equations for multiplicities in QCD cascades can, both in the parton and dipole picture, be used to estimate corrections beyond the formal accuracy of the modified leading log approximation (MLLA). The differences between the two…

For the heavy quarkonium system we examine ${\cal O}(\Lambda_{\rm QCD}^2/m)$ renormalons, which are expected to be included in the perturbative series of the pole mass and $1/(mr^2)$ interquark potential. We find indications of existence…

The anomalous dimensions for the interpolating currents of baryons are indispensable inputs in a serious QCD analysis of baryon. However, the results in the literature are vague. In view of this, in this work, we investigate the one-loop…

A short review is given of the present status of the studies of genuine confinement effects in multiple hadron production in hard processes

In the dispersive approach of Dokshitzer, Marchesini and Webber, standard power-behaved contributions of infrared origin are described with the notion of an infrared regular QCD coupling. I argue that their framework suggests the existence…

We consider the infrared sensitivity of the inclusive heavy quark decay width in perturbation theory. It is shown by explicit calculations to the second loop order (when the non-abelian nature of the QCD interactions first become apparent)…

There are indications of a faith transition in QCD: The strong coupling may freeze at a sufficiently low value to make PQCD relevant even in the confining regime. The properties of PQCD at low Q^2 depend on the asymptotic field…

Perturbation series in QCD are generally asymptotic and suffer from so-called infrared renormalon ambiguities. In the context of the standard operator product expansion in MS-bar these ambiguities are compensated by matrix elements of…

Power corrections to the Q**2 behaviour of the low-order moments of both the longitudinal and transverse structure functions of proton and deuteron have been investigated using available phenomenological fits of existing data in the Q**2…

The problem of precise evaluation of the perturbative QCD predictions at moderate energies is considered. Substantial renormalization scheme dependence of the perturbative predictions obtained with the conventional renormalization group…