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A. V. Kotikov

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

At least 37 records · Page 2Linked to original sources
arXiv2024

α_s from DIS data with large $x$ resummations

The deep inelastic scattering data on the nucleon F_2 structure function, accumulated by BCDMS, SLAC and NMC collaborations in fixed-target experiments, are analyzed in the non-singlet approximation within the frameworks of both conventional \overline{\mathbf{MS}} scheme as well as those with resummations of logarithms at large Bjorken x values. The use of the latter is important because they greatly modify the values of the twist four corrections while leaving a strong coupling constant almost intact.

hep-ph↗
arXiv2023

TMD gluon density in nuclei versus experimental data on heavy flavor production at LHC

Analytical expressions for the Transverse Momentum Dependent (TMD, or unintegrated) gluon and sea quark densities in nuclei are derived at leading order of QCD running coupling. The calculations are performed in the framework of the rescaling model and Kimber-Martin-Ryskin (KMR) prescription, where the Bessel-inspired behavior of parton densities at small Bjorken $x$ values, obtained in the case of flat initial conditions in the double scaling QCD approximation, is applied. The derived expressions are used to evaluate the inclusive heavy flavor production in proton-lead collisions at the LHC. We find a good agreement of our results with latest experimental data collected by the CMS and ALICE Collaborations at $\sqrt s = 5.02$ GeV.

hep-ph↗
arXiv2023

Linearly polarized gluon density at low x

Based on a solution of DGLAP evolution equations at small values of Bjorken variable x, a simple analytic approximation for so-called linearly polarized gluon density \tilde{h}_1^{\perp g}(x,k_t^2, Q^2) is obtained at LO of perturbation theory.

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arXiv2023

Bjorken sum rule with analytic coupling at low Q2 values

The experimental data obtained for the polarized Bjorken sum rule Γ^{(p-n)}_1(Q^2) for small values of Q2 are approximated by the predictions obtained in the framework of analytic QCD up to the 5th order perturbation theory, whose coupling constant does not contain the Landau pole. We found an excellent agreement between the experimental data and the predictions of analytic QCD, as well as a strong difference between these data and the results obtained in the framework of standard QCD.

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arXiv2023

On ultrahigh-energy neutrino-nucleon deep-inelastic scattering and the Froissart bound

A brief review of the results for the total cross section σ^{νN} of ultrahigh-energy neutrino deep inelastic scattering on isoscalar nuclear targets is presented. These results are based on simple approximations for σ^{νN} and are compared with the experimental data of the IceCube Collaboration. The total cross section σ^{νN} is proportional to the structure function F_2^{νN}(M_V^2/s,M_V^2), where M_V is the intermediate boson mass and s is square of the energy of the center of mass. The coefficient in the front of F_2^{νN}(M_V^2/s,M_V^2) depends on the asymptotic behavior of F_2^{νN} at low values of x. It contains an additional term \sim \ln{s} if F_2^{νN} is scaled by the power \ln(1/x). Therefore, the asymptotic behavior of F_2^{νN}\propto\ln^2(1/x) for small x often assumed in the literature already leads to violation of the Froissart bound for σ^{νN}.

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arXiv2023

Short review of interaction effects in graphene

We review field theoretical studies dedicated to understanding the effects of electron-electron interaction in graphene, which is characterized by gapless bands, strong electron-electron interactions, and emerging Lorentz invariance deep in the infrared. We consider the influence of interactions on the transport properties of the system as well as their supposedly decisive influence on the potential dynamical generation of a gap.

hep-th↗
arXiv2023

On Landau-Khalatnikov-Fradkin transformation in quenched QED3

We present the results of studies [1,2] of the gauge covariance of the massless fermion propagator in three-dimensional quenched quantum electrodynamics in the framework of dimensional regularization in d=3-2\ep. Assuming the finiteness of the perturbative expansion, i.e. existence of the limit \ep \to 0, it was shown in [1] that exactly for d=3 all odd perturbative coefficients, starting from the third order, must be equal to zero in any gauge. To test this, in Ref. [2] we calculated three- and four-loop corrections to the massless fermionic propagator. Three-loop corrections are finite and gauge-invariant, while four-loop corrections have singularities. The terms depending on the gauge parameter are completely determined by the lower orders in accordance with the Landau-Khalatnikov-Fradkin transformation.

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arXiv2023

Fractional Analytic QCD beyond Leading Order

Fractional analytic QCD is constructed beyond leading order using the standard inverse logarithmic expansion. It is shown that, contrary to the usual QCD coupling constant, for which this expansion can be used only for large values of its argument, in the case of analytic QCD, the inverse logarithmic expansion is applicable for all values of the argument of the analytic coupling constant. We present four different views, two of which are based primarily on Polylogarithms and generalized Euler $ζ$-functions, and the other two are based on dispersion integrals. The results obtained up to the 5th order of perturbation theory, have a compact form and do not contain complex special functions that were used to solve this problem earlier. As an example, we apply our results to study the polarized Bjorken sum rule, which is currently measured very accurately.

hep-ph↗
arXiv2023

Fractional Analytic QCD beyond Leading Order in timelike region

In this paper we show that, as in the spacelike case, the inverse logarithmic expansion is applicable for all values of the argument of the analytic coupling constant. We present two different approaches, one of which is based primarily on trigonometric functions, and the latter is based on dispersion integrals. The results obtained up to the 5th order of perturbation theory, have a compact form and their acquiring is much easier than the methods that have been used before. As an example, we apply our results to study the Higgs boson decay into a bb pair.

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arXiv2023

About Fractional Analytic QCD

We present a brief overview of fractional analytic QCD, basically following the results recently obtained in Refs. [1,2].

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arXiv2023

On x-independence of RQ = FLQ/F2Q ratio at low x

We give predictions for the ratio RQ(x,Q2)=FLQ(x,Q2)/F2Q(x,Q2) at small values of Bjorken variable x in the first three orders of perturbation theory. We show an approximate x-independence of RQ(x,Q2) at low x and non-large Q2 values (Q2 < 8--10 m2Q), irrespectively on the gluon density in a proton used in the calculations. This observation could be useful in subsequent phenomenological studies of the heavy flavor production at future lepton-hadron and hadron-hadron colliders.

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arXiv2022

Sunrise integral in non-relativistic QCD with elliptics

The main steps of the process of obtaining the result [1] in terms of elliptic polylogarithms for a two-loop sunrise integral with two different internal masses with pseudothreshold kinematics for all orders of the dimensional regulator are shown.

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arXiv2022

Parametrizations of collinear and k_T-dependent parton densities in a proton

A new type of parametrization for parton distribution functions in a proton, based on their $Q^2$-evolution at large and small $x$ values, is constructed. In our analysis, the valence and nonsinglet parts obey the Gross-Llewellyn-Smith and Gottfried sum rules, respectively. For the singlet quark and gluon densities momentum conservation is taken into account. Then, using the Kimber-Martin-Ryskin prescription, we extend the consideration to Transverse Momentum Dependent (TMD, or unintegrated) gluon and quark distributions in a proton, which currently plays an important role in a number of phenomenological applications. The analytical expressions for the latter, valid for both low and large $x$, are derived for the first time.

hep-ph↗
arXiv2022

About Fractional Analytic QCD beyond Leading Order

We present an overview of fractional analytic QCD beyond leading order, following the results recently obtained in Ref. [1]. We demonstrate four different representations, the details of their derivation, and show the applicability of analytic QCD to the analysis of the Bjorken sum rule.

hep-ph↗
arXiv2022

On series and integral representations of some NRQCD master integrals

We consider new ways of obtaining series and integral representations for master integrals arising in the process of matching of QCD to NRQCD. The latter results are exact in space-time dimension $d$. In addition, we discuss series expansion of the obtained results at fixed values of $d$.

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