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Johan Rathsman. Photo.

Johan Rathsman

Senior lecturer

Johan Rathsman. Photo.

Behavior of the effective QCD coupling α τ(s) at low scales

Author

  • Stanley J. Brodsky
  • Sven Menke
  • Carlos Merino
  • Johan Rathsman

Summary, in English

The hadronic decays of the τ lepton can be used to determine the effective charge ατ(m τ2,) for a hypothetical τ lepton with a mass in the range 0<m τ,<mτ. This definition provides a fundamental definition of the QCD coupling at low mass scales. We study the behavior of α τ at low mass scales directly from first principles and without any renormalization-scheme dependence by looking at the experimental data from the OPAL Collaboration. The results are consistent with the freezing of the physical coupling at mass scales s = m τ2, of order 1 GeV 2 with a magnitude α τ ∼0.9 ±0.1.

Publishing year

2003-12-01

Language

English

Publication/Series

Physical Review D

Volume

67

Issue

5

Document type

Journal article

Publisher

American Physical Society

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0556-2821