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A. V. Sidorov

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

At least 37 records · Page 2Linked to original sources
arXiv2001

Application of new multiloop QCD input to the analysis of $xF_3$ data

The new theoretical input to the analysis of the experimental data of the CCFR collaboration for $F_3$ structure function of $νN$ deep inelastic scattering is considered. This input comes from the next-to-next-to-leading order corrections to the anomalous dimensions of the Mellin moments of the $F_3$ structure function. The QCD scale $Λ_{\overline{MS}}^{(4)}$ is extracted from higher-twist independent fits. The results obtained demonstrate the minimization of the influence of perturbative QCD contributions to the value of $Λ_{\overline{MS}}^{(4)}$

hep-ph↗
arXiv2000

Nuclear effects and higher twists in F3 structure function

We analyze the CCFR collaboration iron target data on the xF3 structure function making particular emphasis on the extraction of the higher twist contributions from data. Corrections for nuclear effects are applied in order to extract data on the structure function of the isoscalar nucleon. Our analysis confirms the observation made earlier, that the higher twist terms depend strongly on the level to which QCD perturbation theory analysis is applied. We discuss the impact of nuclear effects on the higher twist term as well as on the QCD scale parameter Lambda_{\bar{MS}} extracted from the fit to data.

hep-ph↗
arXiv2000

QCD

We discuss issues of QCD at the LHC including parton distributions, Monte Carlo event generators, the available next-to-leading order calculations, resummation, photon production, small x physics, double parton scattering, and backgrounds to Higgs production.

hep-ph↗
arXiv2000

On the Sensitivity of the Polarized Parton Densities to Flavour SU(3) Symmetry Breaking

Motivated by the possibility that it may be misleading to assume SU(3) symmetry in the analysis of hyperon β-decays, we study the sensitivity of the polarized parton densities, derived from the world data on inclusive polarized deep inelastic lepton-nucleon scattering, to variation of the value of the nonsinglet axial charge a_8 from its SU(3) value of 3F-D.

hep-ph↗
arXiv2000

The interplay between perturbative QCD and power corrections: the description of scaling or automodelling limit violation in deep-inelastic scattering

The summary of the results of our next-to-next-to-leading fits of Tevatron experimental data for $xF_3$ structure function of the $νN$ deep-inelastic scattering is given. The special attention is paid to the extraction of twist-4 contributions and demonstration of the interplay between these effects and higher-order perturbative QCD corrections. The factorization and renormalization scale uncertainties of the results obtained are analysed

hep-ph↗
arXiv1999

Higher twists and $α_s(M_Z)$ extractions from the NNLO QCD analysis of the CCFR data for $xF_3$ structure function

A detailed next-to-next-to-leading order (NNLO) QCD analysis is performed for the experimental data of the CCFR collaboration for the $xF_3$ structure function. Theoretical ambiguities of the results of our NNLO fits are estimated by application of the Padé resummation technique and variation of the factorization and renormalization scales. The NNLO and N$^3$LO $α_s(Q^2)$ $\bar{MS}$-matching conditions are used. In the process of the fits we are taking into account of twist-4 $1/Q^2$-terms. We found that the amplitude of the $x$-shape of the twist-4 factor is decreasing in NLO and NNLO, though some remaining twist-4 structure seems to retain in NNLO in the case when statistical uncertainties are taken into account. The question of the stability of these results to the application of the [0/2] Padé resummation technique is considered. Our NNLO results for $α_s(M_Z)$ values, extracted from the CCFR $xF_3$ data, are $α_s(M_Z)=0.118 \pm 0.002 (stat) \pm 0.005 (syst)\pm 0.003 (theory)$ provided the twist-4 contributions are fixed through the infrared renormalon model and $α_s(M_Z)=0.121^{+0.007}_{0.010}(stat)\pm 0.005 (syst) \pm 0.003 (theory)$ provided the twist-4 terms are considered as free parameters.

hep-ph↗
arXiv1999

Measurement of $xF_3$ and $F_2$ Structure Functions in Low $Q^2$ Region with the IHEP-JINR Neutrino Detector

The isoscalar structure functions $xF_3$ and $F_2$ are measured as functions of $x$ averaged over all $Q^2$ permissible for the range of 6 to 28 GeV of incident neutrino (anti-neutrino) energy at the IHEP-JINR Neutrino Detector. The QCD analysis of $xF_3$ structure function provides $Λ_{\bar{MS}}^{(4)} = (411 \pm 200)$ MeV under the assumption of QCD validity in the region of low $Q^2$. The corresponding value of the strong interaction constant $α_S (M_Z) = 0.123^{+0.010}_{-0.013}$ agrees with the recent result of the CCFR collaboration and with the combined LEP/SLC result.

hep-ex↗
arXiv1999

The NNLO QCD analysis of the CCFR data for xF_3: is there still the room for the twist-4 terms?

The results of the more detailed NNLO QCD analysis of the CCFR data for $xF_3$ SF are presented. The factorization scale uncertainties are analysed. The NNLO results for $alpha_s(M_Z)$ and twist-4 contributions are obtained. Despite the fact that the amplitude of the $x$-shape of the twist-4 factor is consequently decreasing at the NLO and NNLO, our new QCD analysis seems to reveal the remaining twist-4 structure at the NNLO level. The definite N$^3$LO uncertainties are fixed using the [0/2] Padé resummation technique.

hep-ph↗
arXiv1998

QCD analysis of $xF_3$ structure function data and power correction to $α_s$

Power corrections both to the strong coupling constant and to the structure function itself are estimated on the basis of the LO, NLO and NNLO QCD analysis of $xF_3$ structure function data. The sign of correction to the coupling constant is found to be negative. The x-shape of a higher twist contribution to the structure function is stable up to NNLO.

hep-ph↗
arXiv1998

The QCD analysis of the CCFR data for $xF_3$: higher twists and $α_s(M_Z)$ extractions at the NNLO and beyond

The improved next-to-next-to-leading order (NNLO) QCD analysis of the experimental data of the CCFR collaboration for the $xF_3$ structure function is made. Theoretical ambiguities of the NNLO fits are estimated by means of the Padé resummation technique, which was applied both in the expanded and non-expanded forms. The NNLO and the new N$^3$LO $α_s(Q^2)$ $\bar{MS}$-matching conditions are used. In the process of the fits we are taking into account the target mas corrections and the twist-4 $1/Q^2$-terms. Our NNLO results for $α_s(M_Z)$ values, extracted from the CCFR $xF_3$ data, are $α_s(M_Z)=0.118 \pm 0.002 (stat)\pm 0.005 (syst) \pm 0.003(theory)$ provided the twist-4 contributions are fixed through the infrared renormalon model and $α_s(M_Z)=0.116^{+ 0.006}_{-0.007}(stat)\pm 0.005 (syst) \pm 0.004(theory)$ provided the twist-4 terms are considered as the free parameters. It is shown that the extracted at the NNLO order $x$-shape of the twist-4 correction is almost unchanged after application of the Padé resummation approximant.

hep-ph↗
arXiv1998

Scheme Dependence in Polarized Deep Inelastic Scattering

We study the effect of scheme dependence upon the NLO QCD analysis of the world data on polarized DIS. The reliability of an analysis at NLO is demonstrated by the consistency of our polarized densities with the NLO transformation rules relating them to each other. We stress the importance of the chiral JET scheme in which all the hard effects are consistently absorbed in the Wilson coefficient functions.

hep-ph↗
arXiv1998

Polarized Parton Densities in the Nucleon

We present a critical assessment of what can be learnt from the present data on inclusive polarized DIS. We examine critically some of the simplifying assumptions made in recent analyses and study in detail the question of the determination of the gluon, strange sea and valence quark polarized densities. We have also carried out a new NLO QCD analysis of the world data. We find an excellent fit to the data and present our results for the polarized parton densities.

hep-ph↗
arXiv1997

The QCD analysis of the revised CCFR data for xF_3 structure function: the next-to-next-to-leading order and Padé approximants

The next-to-next-to-leading order (NNLO) QCD analysis of the revised experimental data of the CCFR collaboration for the $xF_3$ structure function of the deep-inelastic scattering of neutrinos and antinuetrinos on the nucleons is made by means of the Jacobi polynomial expansion technique. The NNLO values of the QCD coupling constant are determined both without and with twist--4 contributions taken into account. Theoretical ambiguities of $α_s$ are fixed using the methods of the Padé approximants. We observe that the [0/2] Padé approximant is more appropriate for this purpose than the [1/1] one.

hep-ph↗
arXiv1997

NLO QCD Analysis of Polarized Deep Inelastic Scattering

We have carried out a NLO analysis of the world data on polarized DIS in the MS/bare scheme. We have studied two models of the parametrizations of the input parton densities, the first due to Brodsky, Burkhardt and Schmidt (BBS) which gives a simultaneous parametrization for both the polarized and unpolarized densities and in which the counting rules are strictly imposed, the second in which the input polarized densities are written in terms of the unpolarized ones in the generic form Deltaq(x)=f(x)q(x) with f(x) some simple smooth function. In both cases a good fit to the polarized data is achieved. As expected the polarized data do not allow a precise determination of the polarized gluon density. Concerning the polarized sea-quark densities, these are fairly well determined in the BBS model because of the interplay of polarized and unpolarized data, whereas in the second model, where only the polarized data are relevant, the polarized sea-quark densities are largely undetermined.

hep-ph↗
arXiv1997

Continuous mass-dependent analysis of the non-singlet $xF_3$ CCFR data

We consider the issue of an accurate description of the evolution of the non-singlet structure function moments $M_n(Q)$ near heavy quark threshold. To this aim we propose a simple modification of the standard massless \MSbar scheme approach to the next-to-leading QCD analysis of DIS data. We apply it to the processing of the modern CCFR'97 data for $xF_3$ structure function and extract the value of $α_s(M_z) \approx 0.122 \pm 0.004$ We check also the consistency of light gluino hypothesis with CCFR'97 data.

hep-ph↗
arXiv1997

NNLO QCD Analysis of CCFR data on $xF_3$ Structure Function and Gross-Llewellyn Smith Sum Rule with Higher Twist and Nuclear Corrections

A detailed NNLO QCD analysis of new CCFR data on the $xF_3$ structure function including the target mass, higher twist and nuclear corrections was performed and parametrizations of the perturbative and power terms of the structure function were constructed. The results of QCD analysis of the structure function were used to study the $Q^2-$dependence of the Gross-Llewellyn Smith sum rule. The $α_S/π-$expansion of $S_{GLS}(Q^2)$ was studied and parameters of the expansion were found to be $s_1=2.74\pm 0.01$, $s_2=-2.22\pm 0.23$, $s_3=-7.86\pm 1.74$ in a good agreement with the perturbative QCD predictions for the Gross-Llewellyn Smith sum rule in the next-to-leading and next-to-next-to-leading order.

hep-ph↗