Fragmentation functions using e+e- data from PETRA and LEP

TL;DR

This paper analyzes charged particle fragmentation in e+e- annihilation across various energies, determining the strong coupling constant and studying the scale dependence of fragmentation functions using data from PETRA, LEP, and OPAL.

Contribution

It provides new measurements of the longitudinal cross-section ratio, extracts the strong coupling constant at different energies, and investigates the flavor dependence of the fragmentation scale parameter $\xi_0$.

Findings

Measured $\sigma_L / \sigma_{tot}$ as 0.076 ± 0.013 at 36.6 GeV.

Determined $\alpha_S(36.6 GeV)$ as 0.150 ± 0.025.

Studied the energy dependence of the $\xi_0$ distribution and flavor effects.

Abstract

We investigate fragmentation of charged particles in e+e- annihilation at 22, 35 and 44 GeV in terms of their polar angle and momentum distributions. From the angular distribution the ratio of longitudinal to total hadronic cross-section was determined at an average energy scale of 36.6 GeV to be $\sigma_L / \sigma_{tot} = 0.076 \pm 0.013$. At next-to-leading order this yields $ \alpha_S (36.6 GeV) = 0.150 \pm 0.025 $. The $\xi = \ln (1/x)$ distributions were used in conjunction with OPAL data from 91-208 GeV to study the scale dependence of the maximum position, $\xi_0$. We studied flavour dependence of $\xi_0$ as a possible explanation of this problem, using direct flavour dependent measurements of $\xi_0$ at 91 GeV by OPAL.