Measurements of $\alpha_s$ from event shapes and the four-jet rate

TL;DR

This paper presents new measurements of the strong coupling constant $oldsymbol{ ext{α}_s}$ at LEP using event shapes, four-jet rates, and power corrections, including a novel method for estimating theoretical uncertainties.

Contribution

It introduces a new LEP combination of results with an innovative approach to estimate theoretical uncertainties and compares different analysis methods for measuring $ ext{α}_s$.

Findings

Consistent $ ext{α}_s$ values across different methods.

Improved precision in $ ext{α}_s$ measurement.

Validation of power correction and four-jet rate analyses.

Abstract

New results from measurements of the strong coupling constant $\alpha_s(M_Z)$ at LEP are presented. In particular, a new LEP combination of results based on event-shape variables has become available, where a new method for the estimation of the theoretical uncertainty has been implemented. Furthermore, two other analyses are quoted, based on power corrections and the four-jet rate.