Measurement of the strong coupling constant αs and the vector and axial-vector spectral functions in hadronic tau decays the opal collaboration

OPAL Collaboration

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326 Scopus citations

Abstract

The spectral functions of the vector current and the axial-vector current have been measured in hadronic τ decays using the OPAL detector at LEP. Within the framework of the Operator Product Expansion a simultaneous determination of the strong coupling constant αs, the non-perturbative operators of dimension 6 and 8 and of the gluon condensate has been performed. Different perturbative descriptions have been compared to the data. The Contour Improved Fixed Order Perturbation Theory gives αs(mτ2) = 0.348 ± 0.009exp ± 0.019theo at the τ-mass scale and αs(mZ2) = 0.1219 ± 0.0010exp ± 0.0017theo at the Z°- mass scale. The values obtained for αs(mZ2) using Fixed Order Perturbation Theory or Renormalon Chain Resummation are 2.3% and 4.1% smaller, respectively. The 'running' of the strong coupling between S0 ≃ 1.3 GeV2 and S0 = mτ2 has been tested from direct fits to the integrated differential hadronic decay rate Rτ(s0). A test of the saturation of QCD sum rules at the τ-mass scale has been performed.

Original languageEnglish
Pages (from-to)571-593
Number of pages23
JournalEuropean Physical Journal C
Volume7
Issue number4
DOIs
StatePublished - 1 Jan 1999
Externally publishedYes

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • Physics and Astronomy (miscellaneous)

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