Review of the measurements of the strong coupling constant at LEP 2

TL;DR

This paper reviews and summarizes measurements of the strong coupling constant alpha_s at LEP 2 energies, combining new results from multiple experiments to update the LEP average value.

Contribution

It provides a comprehensive summary and combination of alpha_s measurements at LEP 2 energies, updating the world average of alpha_s(M_Z).

Findings

Updated LEP average alpha_s(M_Z) = 0.120 +- 0.005

New measurements at energies 133, 161, 172 GeV

Consistent results across multiple experiments

Abstract

Since 1995, LEP has steadily increased the center of mass energy of the colliding beams, from the M_Z resonance to 133, 161 and 172 GeV. New measurements of the strong coupling constant, alpha_s, at these energies have been performed by the LEP experiments, L3, ALEPH, OPAL and DELPHI. In this article, the new results are summarized, and combined with the previous LEP measurement of alpha_s(M_Z) in order to obtain an updated LEP average of alpha_s(M_Z) = 0.120 +- 0.005.