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A. V. Nesterenko

Publications and source records attributed to A. V. Nesterenko.

At least 37 records · Page 2Linked to original sources
arXiv2015

Hadronic vacuum polarization function within dispersive approach to QCD

The dispersive approach to quantum chromodynamics is applied to the study of the hadronic vacuum polarization function and associated quantities. This approach merges the intrinsically nonperturbative constraints, which originate in the kinematic restrictions on the respective physical processes, with corresponding perturbative input. The obtained hadronic vacuum polarization function agrees with pertinent lattice simulation data. The evaluated hadronic contributions to the muon anomalous magnetic moment and to the shift of the electromagnetic fine structure constant conform with recent assessments of these quantities.

hep-ph↗
arXiv2014

Dispersive approach to QCD: tau lepton hadronic decay in vector and axial-vector channels

The dispersive approach to QCD, which extends the applicability range of perturbation theory towards the infrared domain, is developed. This approach properly accounts for the intrinsically nonperturbative constraints, which originate in the low-energy kinematic restrictions on pertinent strong interaction processes. The dispersive approach proves to be capable of describing OPAL (update 2012) and ALEPH (update 2014) experimental data on inclusive tau lepton hadronic decay in vector and axial-vector channels in a self-consistent way.

hep-ph↗
arXiv2014

Macroscopic approach to the Casimir friction force

The general formula is derived for the vacuum friction force between two parallel perfectly flat planes bounding two material media separated by a vacuum gap and moving relative to each other with a constant velocity $\mathbf{v}$. The material media are described in the framework of macroscopic electrodynamics whereas the nonzero temperature and dissipation are taken into account by making use of the Kubo formulae from non-equilibrium statistical thermodynamics. The formula obtained provides a rigorous basis for calculation of the vacuum friction force within the quantum field theory methods in the condensed matter physics. The revealed $v$-dependence of the vacuum friction force proves to be the following: for zero temperature ($T=0$) it is proportional to $(v/c)^3$ and for $T>0$ this force is linear in $(v/c)$.

quant-ph↗
arXiv2013

Dispersive approach to QCD and inclusive tau lepton hadronic decay

The dispersive approach to QCD is applied to the study of the inclusive tau lepton hadronic decay. This approach provides the unified integral representations for the hadronic vacuum polarization function, related R function, and Adler function. These representations account for the intrinsically nonperturbative constraints, which originate in the kinematic restrictions on the functions on hand, and retain the effects due to hadronization, which play a valuable role in the analysis of the strong interaction processes at low energies. The dispersive approach proves to be capable of describing recently updated ALEPH and OPAL experimental data on inclusive tau lepton hadronic decay in vector and axial-vector channels. The vicinity of values of the QCD scale parameter obtained in both channels testifies to the potential ability of the developed approach to describe the aforementioned data in a self-consistent way.

hep-ph↗
arXiv2012

Hadronic effects in low-energy QCD: inclusive tau lepton decay

The inclusive tau lepton hadronic decay is studied within Dispersive approach to QCD. The significance of effects due to hadronization is convincingly demonstrated. The approach on hand proves to be capable of describing experimental data on tau lepton hadronic decay in vector and axial-vector channels. The vicinity of values of QCD scale parameter obtained in both channels bears witness to the self-consistency of developed approach.

hep-ph↗
arXiv2011

Hadronization effects in inclusive tau decay

It is shown that the nonperturbative effects due to hadronization play a crucial role in low-energy strong interaction processes. Specifically, such effects impose a stringent constraint on the infrared behavior of the Adler function and play an essential role in the theoretical analysis of inclusive tau lepton decay.

hep-ph↗
arXiv2011

The effects due to hadronization in the inclusive tau lepton decay

Theoretical description of inclusive tau lepton hadronic decay is performed in the framework of Dispersive approach to QCD. The significance of effects due to hadronization is demonstrated. The approach on hand is capable of describing experimental data on tau lepton decay in vector and axial-vector channels. The vicinity of values of QCD scale parameter obtained in both channels testifies to the self-consistency of developed approach.

hep-ph↗
arXiv2011

QCDMAPT_F: Fortran version of QCDMAPT package

The QCDMAPT program package facilitates computations in the framework of dispersive approach to Quantum Chromodynamics. The QCDMAPT_F version of this package enables one to perform such computations with Fortran, whereas the previous version was developed for use with Maple system. The QCDMAPT_F package possesses the same basic features as its previous version. Namely, it embodies the calculated explicit expressions for relevant spectral functions up to the four-loop level and the subroutines for necessary integrals.

hep-ph↗
arXiv2010

A nonperturbative model for the strong running coupling within potential approach

A nonperturbative model for the QCD invariant charge, which contains no low-energy unphysical singularities and possesses an elevated higher loop corrections stability, is developed in the framework of potential approach. The static quark-antiquark potential is constructed by making use of the proposed model for the strong running coupling. The obtained result coincides with the perturbative potential at small distances and agrees with relevant lattice simulation data in the nonperturbative physically-relevant region. The developed model yields a reasonable value of the QCD scale parameter, which is consistent with its previous estimations obtained within potential approach.

hep-ph↗
arXiv2010

QCDMAPT: program package for Analytic approach to QCD

A program package, which facilitates computations in the framework of Analytic approach to QCD, is developed and described in details. The package includes the explicit expressions for relevant spectral functions calculated up to the four-loop level and the subroutines for necessary integrals.

hep-ph↗
arXiv2008

On the low-energy behavior of the Adler function

The infrared behavior of the Adler function is examined by making use of a recently derived integral representation for the latter. The obtained result for the Adler function agrees with its experimental prediction in the entire energy range. The inclusive $τ$ lepton decay is studied in the framework of the developed approach.

hep-ph↗
arXiv2007

Bound state approach to the QCD coupling at low energy scales

We exploit theoretical results on the meson spectrum within the framework of a Bethe-Salpeter (BS) formalism adjusted for QCD, in order to extract an ``experimental'' coupling α_s^{exp}(Q^2) below 1 GeV by comparison with the data. Our results for α_s^{exp}(Q^2) exhibit a good agreement with the infrared safe Analytic Perturbation Theory (APT) coupling from 1 GeV down to 200 MeV. As a main result, we claim that the combined BS-APT theoretical scheme provides us with a rather satisfactory correlated understanding of very high and low energy phenomena.

hep-ph↗
arXiv2007

Adler function in the analytic approach to QCD

The low energy behavior of the Adler function D(Q^2) is studied by employing recently derived integral representation for the latter. This representation embodies the nonperturbative constraints on D(Q^2), in particular, it retains the effects due to the nonvanishing pion mass. The Adler function is calculated within the developed approach by making use of its perturbative approximation as the only additional input. The obtained result agrees with the experimental prediction for the Adler function in the entire energy range and possesses remarkable stability with respect to the higher loop corrections.

hep-ph↗
arXiv2007

QCD coupling below 1 GeV from quarkonium spectrum

In this paper we extend the work synthetically presented in Ref.[1] and give theoretical details and complete tables of numerical results. We exploit calculations within a Bethe-Salpeter (BS) formalism adjusted for QCD, in order to extract an ``experimental'' strong coupling α_s^{exp}(Q^2) below 1 GeV by comparison with the meson spectrum. The BS potential follows from a proper ansatz on the Wilson loop to encode confinement and is the sum of a one-gluon-exchange and a confinement terms. Besides, the common perturbative strong coupling is replaced by the ghost-free expression α_E(Q^2) according to the prescription of Analytic Perturbation Theory (APT). The agreement of α_s^{exp}(Q^2) with the APT coupling α_E(Q^2) turns out to be reasonable from 1 GeV down to the 200 MeV scale, thus confirming quantitatively the validity of the APT prescription. Below this scale, the experimental points could give a hint on the vanishing of α_s(Q^2) as Q approaches zero. This infrared behaviour would be consistent with some lattice results and a ``massive'' generalization of the APT approach. As a main result, we claim that the combined BS-APT theoretical scheme provides us with a rather satisfactory correlated understanding of very high and rather low energy phenomena from few hundreds MeV to few hundreds GeV.

hep-ph↗
arXiv2006

A novel integral representation for the Adler function

New integral representations for the Adler D-function and the R-ratio of the electron-positron annihilation into hadrons are derived in the general framework of the analytic approach to QCD. These representations capture the nonperturbative information encoded in the dispersion relation for the D-function, the effects due to the interrelation between spacelike and timelike domains, and the effects due to the nonvanishing pion mass. The latter plays a crucial role in this analysis, forcing the Adler function to vanish in the infrared limit. Within the developed approach the D-function is calculated by employing its perturbative approximation as the only additional input. The obtained result is found to be in reasonable agreement with the experimental prediction for the Adler function in the entire range of momenta $0 \le Q^2 < \infty$.

hep-ph↗
arXiv2005

Quark gap equation within the analytic approach to QCD

The compatibility between the QCD analytic invariant charge and chiral symmetry breaking is examined in detail. The coupling in question incorporates asymptotic freedom and infrared enhancement into a single expression, and contains only one adjustable parameter with dimension of mass. When inserted into the standard form of the quark gap-equation it gives rise to solutions displaying singular confining behavior at the origin. By relating these solutions to the pion decay constant, a rough estimate of about 880 MeV is obtained for the aforementioned mass-scale.

hep-ph↗