Review of alpha_s determinations

TL;DR

This paper reviews the most precise measurements of the strong coupling constant alpha_s across various energies, demonstrating a remarkable agreement with QCD predictions and confirming Asymptotic Freedom as fundamental to strong interactions.

Contribution

It provides a comprehensive summary of alpha_s determinations and confirms the consistency of experimental results with QCD running at the Z mass scale.

Findings

Alpha_s(M_Z^2)= 0.1186  0.0007

Strong agreement between measurements and QCD predictions

Validation of Asymptotic Freedom as fundamental

Abstract

The present knowledge on the strong coupling is briefly summarized. The most precise determinations of alpha_s, at different energies, are reviewed and compared at the Z mass scale, using the predicted QCD running. The impressive agreement achieved between experimental measurements and theoretical predictions constitutes a beautiful and very significant test of Asymptotic Freedom, establishing QCD as the fundamental theory of the strong interaction. The world average value of the strong coupling is found to be alpha_s(M_Z^2)= 0.1186 \pm 0.0007.