Study of moments of event shapes and a determination of \as using \epem annihilation data from \Jade

TL;DR

This paper analyzes event shape moments from extit{e+e-} annihilation data collected by the extit{Jade} experiment at energies 14-44 GeV, comparing measurements with QCD predictions to determine the strong coupling constant extit{ extbf{ extit{ extalpha}_s}}.

Contribution

It provides a measurement of extit{ extalpha}_s at low energies using event shape moments and compares data with NLO QCD, highlighting systematic deficiencies.

Findings

Measured extalpha_s(M_Z) = 0.1287 with uncertainties.

Models with LEP-tuned hadronisation parameters describe low energy data well.

NLO QCD shows deficiencies for some moments.

Abstract

Data from \epem annihilation into hadrons, collected by the \Jade experiment at centre-of-mass energies between 14 GeV and 44 GeV, are used to study moments of event shape distributions. Models with hadronisation parameters tuned to the LEP 1 precision data provide an adequate description of the low energy data studied here. The NLO QCD calculations, however, show systematic deficiencies for some of the moments. The strong coupling measured from the moments which are reasonably described by NLO QCD, \asmz=0.1287\pm0.0007\stat\pm0.0011\expt\pm0.0022\had\pm0.0075\theo is consistent with the world average.