arXiv subjects

I. O. Cherednikov

Publications and source records attributed to I. O. Cherednikov.

43 records · Page 3Linked to original sources

arXiv2008

Renormalization, Wilson lines, and transverse-momentum dependent parton distribution functions

We perform an analysis of transverse-momentum dependent parton distribution functions, making use of their renormalization properties in terms of their leading-order anomalous dimensions. We show that the appropriate Wilson line in the light-cone gauge, associated with such quantities, is a cusped one. To cancel the ensuing cusp anomalous dimension, we include in the definition of the transverse-momentum dependent parton distribution functions an additional soft counter term (gauge link) along that contour. We demonstrate that this is tantamount to an ``intrinsic (Coulomb) phase'', which accumulates the full gauge history of the color-charged particle.

hep-ph↗

arXiv2007

Gauge invariance and renormalization-group effects in transverse-momentum dependent parton distribution functions

A range of issues pertaining to the use of Wilson lines in integrated and transverse-momentum dependent (TMD) parton distribution functions (PDF) is discussed. The relation between gauge invariance and the renormalization properties of the Wilson-line integrals is given particular attention. Using an anomalous-dimensions based analysis in the light-cone gauge, a generalized definition of the TMD PDFs is proposed, which employs a cusped Wilson line, and contains an intrinsic "Coulomb-like" phase.

hep-ph↗

arXiv2006

Instanton contribution to the Sivers function

We study the Sivers function for valence u and d quarks in the proton within the instanton model for QCD vacuum, adopting the MIT bag model wave functions for quarks. Within approaches based on perturbative one-gluon final state interactions a non-zero value of the Sivers function is related to the presence of both S and P wave components in quark wave functions. We show that the instanton-induced chromomagnetic, nonperturbative interaction leads to very specific spin-spin correlations between the struck and spectator quarks, resulting in a non-trivial flavour dependence of the Sivers function. Comparison of the obtained Sivers functions with phenomenological parameterizations is discussed.

hep-ph↗

arXiv2005

Feynman rules for effective Regge action

Starting from the gauge invariant effective action in the quasi-multi-Regge kinematics (QMRK), we obtain the effective reggeized gluon (R) -- particle (P) vertices of the following types: $RPP$, $RRP$, $RRPP$, $RPPP$, $RRPPP$, and $RPPPP$, where the on-mass-shell particles are gluons, or sets of gluons with small invariant masses. The explicit expressions satisfying the Bose-symmetry and gauge invariance conditions are obtained. As a comment to the Feynman rules for derivation of the amplitudes in terms of effective vertices we present a ``vocabulary'' for practitioners.

hep-ph↗

arXiv2004

Study of instanton effects in electromagnetic quark form factor at high energy

The detailed analysis of nonperturbative contributions to the electromagnetic quark form factor is performed within the framework of the instanton liquid model (ILM) of the QCD vacuum. The method of the path-ordered Wilson exponentials is applied to evaluate explicitly the instanton corrections. By using the Gaussian interpolation of the constrained instanton solution, it is shown that the instantons yield the logarithmic corrections to the amplitudes in high energy limit which are exponentiated in small instanton density parameter.

hep-ph↗

arXiv2004

Double-logarithmic behavior of inelastic fermion form factors in QED and QCD

The effective kinematic diagram technique is applied to study inelastic form factors of electron and quark in QED and QCD. The explicit expressions for these form factors in the double-logarithmic approximation are presented. The self-consistency of the results is shown by demonstrating the fulfillment of the Kinoshita-Lee-Nauenberg theorem.

hep-ph↗

arXiv2004

Instanton effects in quark form factor and quark-quark scattering at high energy

The nonperturbative effects in the high-energy processes involving strongly interacting particles are studied within the instanton liquid model of the QCD vacuum (ILM) by using the Wilson integral framework. The detailed analysis of nonperturbative contributions to the electromagnetic quark form factor is presented considering the structure of the instanton induced effects in the evolution equation describing the high energy behaviour of the form factor. It is shown that the instantons yield in high energy limit the logarithmic corrections to the amplitudes which are exponentiated in small instanton density parameter. By using the Gaussian interpolation of the constrained instanton solution, we show that the all-order multi-instanton contribution is well approximated by the weak field limit result. The role of the instantons in high energy diffractive quark-quark scattering, in particular, in formation of the soft Pomeron, is also considered. We show that within the ILM the C-odd diffractive amplitude is suppressed as 1/s compared to the C-even one. The further applications of the developed approach in studying the nonperturbative effects in high energy hadronic processes are briefly discussed.

hep-ph↗