V. G. Krivokhijine — Page 2

arXiv2011

Ratios of Helicity Amplitudes for Exclusive rho-0 Electroproduction

Exclusive rho^0-meson electroproduction is studied in the HERMES experiment, using a 27.6 GeV longitudinally polarized electron/positron beam and unpolarized hydrogen and deuterium targets in the kinematic region 0.5 GeV^2 < Q^2 < 7.0 GeV^2, 3.0 GeV < W < 6.3 GeV, and -t' < 0.4 GeV^2. Real and imaginary parts of the ratios of the natural-parity-exchange helicity amplitudes T_{11} (γ^*_T --> ρ_T), T_{01} (γ^*_T --> ρ_L), T_{10} (γ^*_L --> ρ_T), and T_{1-1} (γ^*_{-T} -->ρ_T) to T_{00} (γ^*_L --> ρ_L) are extracted from the data. For the unnatural-parity-exchange amplitude U_{11}, the ratio |U_{11}/T_{00}| is obtained. The Q^2 and t' dependences of these ratios are presented and compared with perturbative QCD predictions.

hep-ex↗

arXiv2003

The value of QCD coupling constant and power corrections in the structure function F2 measurements

We reanalyze deep inelastic scattering data of BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We perform also the fits of high statistic deep inelastic scattering data of BCDMS, SLAC, NM and BFP Collaborations taking the data separately and in combined way and find good agreement between these analyses. We extract the values of both the QCD coupling constant α_s(M^2_Z) up to NLO level and of the power corrections to the structure function F_2.

hep-ph↗

arXiv2002

A study of QCD coupling constant and power corrections in the fixed target deep inelastic measurements

We reanalyze deep inelastic scattering data of BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We perform also the fits of high statistic deep inelastic scattering data of BCDMS, SLAC, NM and BFP Collaborations taking the data separately and in combined way and find good agreement between these analyses. We extract the values of both the QCD coupling constant α_s(M^2_Z) up to NLO level and of the power corrections to the structure function F_2.

hep-ph↗

arXiv2002

QCD coupling constant value and deep inelastic measurements

We reanalyze deep inelastic scattering data of BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We perform also the fits of high statistic deep inelastic scattering data of BCDMS, SLAC, NM and BFP Collaborations taking the data separately and in combined way and find good agreement between these analyses. We extract the values of the QCD coupling constant α_s(M^2_Z) up to NLO level.

hep-ph↗

arXiv2002

A study of QCD coupling constant from fixed target deep inelastic measurements

We reanalyze deep inelastic scattering data of BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We perform also the fits of high statistic deep inelastic scattering data of BCDMS, SLAC, NM and BFP Collaborations taking the data separately and in combined way and find good agreement between these analyses. We extract the values of the QCD coupling constant α_s(M^2_Z) up to NLO level. The fits of the combined data for the nonsinglet part of the structure function F_2 predict the coupling constant value α_s(M^2_Z) = 0.1174 \pm 0.0007 (stat) \pm 0.0019 (syst) \pm 0.0010 (normalization). The fits of the combined data for both: the nonsinglet part of F_2 and the singlet one, lead to the values α_s(M^2_Z) = 0.1177 \pm 0.0007 (stat) \pm 0.0021 (syst) \pm 0.0009 (normalization). Both above values are in very good agreement with each other.

hep-ph↗

arXiv2001

A systematic study of QCD coupling constant from deep inelastic measurements

We reanalyze deep inelastic scattering data of BCDMS Collaboration by including proper cuts of ranges with large systematic errors. We perform also the fits of high statistic deep inelastic scattering data of BCDMS, SLAC, NM and BFP Collaborations taking the data separately and in combined way and find good agreement between these analyses. We extract the values of both the QCD coupling constant α_s(M^2_Z) up to NLO level and of the power corrections to the structure function F_2. The fits of the combined data for the nonsinglet part of the structure function F_2 predict the coupling constant value α_s(M^2_Z) = 0.1174 \pm 0.0007 (stat) \pm 0.0019 (syst) \pm 0.0010 (normalization) (or QCD parameter Λ^{(5)}_{MSbar} = 204 \pm 25 (total exper.err.) MeV). The fits of the combined data for both: the nonsinglet part and the singlet one, lead to the values α_s(M^2_Z) = 0.1177 \pm 0.0007 (stat) \pm 0.0021 (syst) \pm 0.0009 (normalization) (or QCD parameter Λ^{(5)}_{MSbar} = 208 \pm 27 (total exper.err.) MeV). Both above values are in very good agreement with each other. We estimate theoretical uncertainties for α_s(M^2_Z) as +0.0047 and -0.0057 from fits of the combine data, when complete singlet and nonsinglet Q^2 evolution is taken into account.

hep-ph↗

arXiv1998

F_2 Structure Function and Higher-twist Contributons (Nonsinglet Case)

We performed the combine fits of SLAC, BCDMS and NMC data at NLO level. The data are fitted very well with different parametrizations of higher twist contributions. The theory-based parametrizations lead to the low values of QCD parameter Λ^{f=4}_{\overfull{MS}} \sim 140 \pm 21 MeV (or α_s(M^2_Z)= 0.103 \pm 0.002).

hep-ph↗