alpha_S Evolution from 35 GeV to 202 GeV and Flavour Independence

TL;DR

This paper measures the strong coupling constant alpha_S across a wide energy range, confirming its energy evolution matches QCD predictions and demonstrating flavour independence when quark mass effects are considered.

Contribution

It provides new measurements of alpha_S at high energies and confirms its flavour independence, extending previous results with combined LEP and lower energy data.

Findings

Alpha_S at 192-202 GeV agrees with QCD predictions.

Combined data yields alpha_S(m_Z)=0.1187^{+0.0034}_{-0.0019}.

Strong coupling is flavour independent with quark mass effects accounted for.

Abstract

Determinations of the strong coupling constant alpha_S at centre-of-mass energies of 192 through 202 GeV at LEP are presented. The energy evolution of alpha_S is in agreement with the prediction of QCD. The combined investigation of OPAL and JADE data in the energy range of 35 through 189 GeV yields alpha_S(m_Z)=0.1187^{+0.0034}_{-0.0019}. The strenght of the strong coupling is flavour independent if quark mass effects are taken into account.