Searcharxiv⌕ Search

arXiv subjects

A. V. Kotikov

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

At least 91 records · Page 5Linked to original sources
arXiv2014

Interaction corrections to the minimal conductivity of graphene via dimensional regularization

We compute the two-loop interaction correction to the minimal conductivity of disorder-free intrinsic graphene with the help of dimensional regularization. The calculation is done in two different ways: via density-density and via current-current correlation functions. Upon properly renormalizing the perturbation theory, in both cases, we find that: $σ= σ_0\,( 1 + \al\,(19-6π)/12) \approx σ_0 \,(1 + 0.01\, \al)$, where $\al = e^2 / (4 π\hbar v)$ is the renormalized fine structure constant and $σ_0 = e^2 / (4 \hbar)$. Our results are consistent with experimental uncertainties and resolve a theoretical dispute.

cond-mat.mes-hall↗
arXiv2014

Q2-evolution of parton densities at small x values. Effective scale for combined H1 and ZEUS F2 data

We use the Bessel-inspired behavior of the structure function F2 at small x, obtained for a flat initial condition in the DGLAP evolution equations. We fix the scale of the coupling constant, which eliminates the singular part of anomalous dimesnions at the next-to-leading order of approximation. The approach together with the "frozen" and analytic modifications of the strong coupling constant is used to study the precise combined H1 and ZEUS data for the structure function F2 published recently.

hep-ph↗
arXiv2014

Q^2-evolution of parton densities at small x values and H1 and ZEUS experimental data

It is shown that in the leading twist approximation of the Wilson operator product expansion with "frozen" and analytic strong coupling constants, considering the Bessel-inspired behavior of the structure functions F2 and the derivative d ln F2/(d ln(1/x)) at small x values, obtained for a flat initial condition in the DGLAP evolution equations,leads to a good agreement with the deep inelastic scattering H1 and ZEUS experimental data from HERA

hep-ph↗
arXiv2014

Two-loop fermion self-energy in reduced quantum electrodynamics and application to the ultra-relativistic limit of graphene

We compute the two-loop fermion self-energy in massless reduced quantum electrodynamics for an arbitrary gauge using the method of integration by parts. Focusing on the limit where the photon field is four-dimensional, our formula involves only recursively one-loop integrals and can therefore be evaluated exactly. From this formula, we deduce the anomalous scaling dimension of the fermion field as well as the renormalized fermion propagator up to two loops. The results are then applied to the ultra-relativistic limit of graphene and compared with similar results obtained for four-dimensional and three-dimensional quantum electrodynamics.

hep-ph↗
arXiv2014

Pomeron in the N=4 supersymmetric gauge model at strong couplings

We find the BFKL Pomeron intercept at N=4 supersymmetric gauge theory in the form of the inverse coupling expansion j0=2-2/lambda**(1/2)-1/lambda + 1/4 1/lambda**(3/2) + 2(1+3zeta3)/lambda**(2) + O(1/lambda**(5/2)) with the use of the AdS/CFT correspondence in terms of string energies calculated recently. The corresponding slope gamma'(2) of the anomalous dimension calculated directly up to the fifth order of perturbation theory turns out to be in an agreement with the closed expression obtained from the recent Basso results.

hep-th↗
arXiv2014

Pomeron in the N=4 SYM at strong couplings

We show the result for the BFKL Pomeron intercept at N=4 Supersymmetric Yang-Mills model in the form of the inverse coupling expansion j0=2-2 lambda**(-1/2)- lambda**(-1) + 1/4 lambda**(-3/2) + 2(1+3zeta3) lambda**(-2) + O(lambda**(-5/2)), which has been calculated recently in [1] with the use of the AdS/CFT correspondence.

hep-th↗
arXiv2013

Gluon- and Quark-Jet Multiplicities with NNNLO and NNLL Accuracy

We present a new approach to consider and include both the perturbative and the non-perturbative contributions to the multiplicities of gluon and quark jets. Thanks to this new method, we have included for the first time new contributions to these quantities obtaining next-to-next-to-leading-logarithmic resummed formulas. Our analytic expressions depend on two non-perturbative parameters with a clear and simple physical interpretation. A global fit of these two quantities shows how our results solve a longstanding discrepancy in the theoretical description of the data.

hep-ph↗
arXiv2012

Small x behavior of parton distributions. Analytical and "frozen" coupling constants. BFKL corrections

It is shown that in the leading twist approximation of the Wilson operator product expansion with "frozen" and analytic strong coupling constants, Bessel-inspired behavior of the structure functions F2 and F2cc and also the derivative d(ln F2)/d(ln(1/x)) at small x values, obtained for a flat initial condition in the DGLAP evolution equations, leads to good agreement with the deep inelastic scattering experimental data from HERA.

hep-ph↗
arXiv2011

Timelike Single-logarithm-resummed Splitting Functions

We calculate the single logarithmic contributions to the quark singlet and gluon matrix of timelike splitting functions at all orders in the modified minimal-subtraction (MSbar) scheme. We fix two of the degrees of freedom of this matrix from the analogous results in the massive-gluon regularization scheme by using the relation between that scheme and the MSbar scheme. We determine this scheme transformation from the double logarithmic contributions to the timelike splitting functions and the coefficient functions of inclusive particle production in e+ e- annihilation now available in both schemes. The remaining two degrees of freedom are fixed by reasonable physical assumptions. The results agree with the fixed-order results at next-to-next-to-leading order in the literature.

hep-ph↗
arXiv2011

Effect of the analytic and frozen coupling constants in QCD up to NNLO from DIS data

We give a short review of our recent analysis [1] of the deep inelastic scattering data (provided by BCDMS, SLAC, NMC) on F2 structure function in the non-singlet approximation with up to next-to-next-to-leading-order accuracy and analytic and frozen modifications of the strong coupling constant featuring no unphysical singularity (the Landau pole). Improvement of agreement between theory and experiment, with respect to the case of the standard perturbative definition of the strong coupling constant considered recently in [2], was observed.

hep-ph↗
arXiv2011

HQET heavy-heavy vertex diagram with two velocities

The one-loop HQET heavy-heavy vertex diagram with arbitrary powers of all three denominators and arbitrary residual energies is investigated. Various particular cases in which the result becomes simpler are considered.

hep-ph↗
arXiv2011

On the critical behavior of (2+1)-dimensional QED

It is shown the analysis [1] for QED in 2+1 dimensions with N four-component fermions in the leading and next-to-leading orders of the 1/N expansion. As it was demonstrated in [1] the range of the admissible values N, where the dynamical fermion mass exist, decreases strongly with the increasing of the gauge charge. So, in Landau gauge the dynamical chiral symmetry breaking appears for N<3.78, that is very close to the results of the leading order and in Feynman gauge dynamical mass is completely absent.

hep-ph↗
arXiv2011

F2c at low x

We study the heavy-quark contributions to the proton structure function F2(x,Q2) at next-to-leading order using compact formulas at small values of Bjorken's x variable. The formulas provide a good agreement with the modern HERA data for F2c(x,Q2).

hep-ph↗
arXiv2010

About QCD coupling constant at NNLO from DIS data

We give a brief review of our recent QCD analysis carried out over the deep inelastic scattering data on F2 structure function and in the non-singlet approximation to the accuracy up to next-to-next-to-leading-order. Specifically, analysis was performed over high statistics deep inelastic scattering data provided by BCDMS, SLAC, NMC and BFP collaborations. For the coupling constant the following value alpha_s(M_Z^2) = 0.1167 \pm 0.0022 was found.

hep-ph↗