On the Behavior of the Effective QCD Coupling alpha_tau(s) at Low Scales
High Energy Physics - Phenomenology
2008-11-26 v3 High Energy Physics - Experiment
High Energy Physics - Theory
Abstract
The hadronic decays of the tau lepton can be used to determine the effective charge alpha_tau(m^2_tau') for a hypothetical tau-lepton with mass in the range 0 < m_tau' < m_tau. This definition provides a fundamental definition of the QCD coupling at low mass scales. We study the behavior of alpha_tau 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^2_tau' of order 1 GeV^2 with a magnitude alpha_tau ~ 0.9 +/- 0.1.
Cite
@article{arxiv.hep-ph/0212078,
title = {On the Behavior of the Effective QCD Coupling alpha_tau(s) at Low Scales},
author = {Stanley J. Brodsky and Sven Menke and Carlos Merino and Johan Rathsman},
journal= {arXiv preprint arXiv:hep-ph/0212078},
year = {2008}
}
Comments
15 pages, 4 figures, submitted to Physical Review D, added references, some text added, no results nor figures changed