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Determination of alpha(S) using OPAL hadronic event shapes at root s=91-209 GeV and resummed NNLO calculations

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  • G. Abbiendi
  • C. Ainsley
  • P. F. Akesson
  • G. Alexander
  • G. Anagnostou
  • K. J. Anderson
  • S. Asai
  • D. Axen
  • I. Bailey
  • E. Barberio
  • T. Barillari
  • R. J. Barlow
  • R. J. Batley
  • P. Bechtle
  • T. Behnke
  • K. W. Bell
  • P. J. Bell
  • G. Bella
  • A. Bellerive
  • G. Benelli
  • S. Bethke
  • O. Biebel
  • O. Boeriu
  • P. Bock
  • M. Boutemeur
  • S. Braibant
  • R. M. Brown
  • H. J. Burckhart
  • S. Campana
  • P. Capiluppi
  • R. K. Carnegie
  • A. A. Carter
  • J. R. Carter
  • C. Y. Chang
  • D. G. Charlton
  • C. Ciocca
  • A. Csilling
  • M. Cuffiani
  • S. Dado
  • M. Dallavalle
  • A. De Roeck
  • E. A. De Wolf
  • K. Desch
  • B. Dienes
  • J. Dubbert
  • E. Duchovni
  • G. Duckeck
  • I. P. Duerdoth
  • E. Etzion
  • F. Fabbri
  • OPAL Collaboration
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Article number1733
<mark>Journal publication date</mark>09/2011
<mark>Journal</mark>European Physical Journal C: Particles and Fields
Issue number9
Volume71
Number of pages21
Pages (from-to)-
Publication statusPublished
Original languageEnglish

Abstract

Hadronic event shape distributions from e(+)e(-) annihilation measured by the OPAL experiment at centre-of-mass energies between 91 GeV and 209 GeV are used to determine the strong coupling alpha(S). The results are based on QCD predictions complete to the next-to-next-to-leading order (NNLO), and on NNLO calculations matched to the re-summed next-to-leading-log-approximation terms (NNLO+NLLA). The combined NNLO result from all variables and centre-of-mass energies is

alpha(S)(m(Z0)) = 0.1201 +/- 0.0008 (stat.) +/- 0.0013(exp.) +/- 0.0010(had.) +/- 0.0024(theo.)

while the combined NNLO + NLLA result is

alpha(S)(m(Z0)) = 0.1189 +/- 0.0008(stat.) +/- 0.0016(exp.) +/- 0.0010(had.) +/- 0.0036(theo.)

The completeness of the NNLO and NNLO + NLLA results with respect to missing higher order contributions, studied by varying the renormalization scale, is improved compared to previous results based on NLO or NLO + NLLA predictions only. The observed energy dependence of alpha(S) agrees with the QCD prediction of asymptotic freedom and excludes the absence of running.