Determination of alpha_s(M_Z^2) from hadronic event shape observables in e+e- annihilation

TL;DR

This paper reviews methods for determining alpha_s(M_Z^2) from e+e- annihilation data, highlighting the impact of higher-order uncertainties and exploring optimized perturbation techniques to improve precision.

Contribution

It introduces the use of optimized perturbation theory and Pade approximants to reduce theoretical uncertainties in alpha_s(M_Z^2) extraction.

Findings

Large scatter in alpha_s(M_Z^2) values from different observables.

Higher-order contributions significantly affect alpha_s(M_Z^2) determinations.

Optimized perturbation methods may help mitigate these effects.

Abstract

The determination of alpha_s(M_Z^2) using O(alpha_s^2) calculations of hadronic event observables in e+e- annihilation is reviewed. The large scatter among alpha_s(M_Z^2) values determined from different observables may be interpreted as arising from the effect of uncalculated higher-order contributions. The application of `optimised' perturbation theory and Pade approximants in an attempt to reduce this effect is discussed.