Tests of analytical hadronisation models using event shape moments in {\epem} annihilation

TL;DR

This paper evaluates analytical hadronisation models against experimental event shape data from electron-positron annihilation, highlighting their parameter efficiency and discussing their limitations due to higher-order effects.

Contribution

It provides a comprehensive comparison of dispersive, shape function, and dressed gluon models with experimental data, emphasizing their parameter simplicity and limitations.

Findings

Analytical models require only two universal parameters.

Extracted strong coupling values align with the world average.

Models show limitations likely due to higher order corrections.

Abstract

Predictions of analytical models for hadronisation, namely the dispersive model, the shape function and the single dressed gluon approximation, are compared with moments of hadronic event shape distributions measured in \epem annihilation at centre-of-mass energies between 14 and 209 GeV. In contrast to Monte Carlo models for hadronisation, analytical models require to adjust only two universal parameters, the strong coupling and a second quantity parametrising nonperturbative corrections. The extracted values of as are consistent with the world average and competitive with previous measurements. The variance of event shape distributions is compared with predictions given by some of these models. Limitations of the models, probably due to unknown higher order corrections, are demonstrated and discussed.