$\alpha_s$ at Zinnowitz 2004

TL;DR

This paper reviews measurements of the strong coupling constant alpha_s as of April 2004, confirming its energy dependence and providing a precise world average value at the Z boson mass scale consistent with QCD predictions.

Contribution

It compiles and analyzes alpha_s measurements up to 2004, evolving them to the Z boson energy, and determines a precise world average using NNLO QCD calculations.

Findings

Alpha_s shows expected energy dependence.

Measurements agree with QCD predictions.

World average alpha_s(M_Z) = 0.1182 ± 0.0027.

Abstract

A review of measurements of $\alpha_s$ is given, representing the status of April 2004. The results prove the energy dependence of $\alpha_s$ and are in excellent agreement with the expectations of Quantum Chromodynamics, QCD. Evolving all results to the rest energy of the $Z^0$ boson, the world average of $\alpha_s(M_Z)$ is determined from measurements which are based on QCD calculations in complete NNLO perturbation theory, giving $\alpha_s(M_Z) = 0.1182 \pm 0.0027 .$