Behavior of the effective QCD coupling α τ(s) at low scales
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.
- Subatomic Physics
- ISSN: 0556-2821