Charged Particles Multiplicity and Scaling Violation of Fragmentation Functions in Electron-Positron Annihilation

TL;DR

This paper investigates the scaling violations of fragmentation functions in electron-positron annihilation, analyzing charged particle multiplicity, momentum spectra, and comparing experimental data with QCD models at 60 GeV.

Contribution

It provides the first detailed analysis of fragmentation function scaling violations using AMY detector data at 60 GeV, including multiplicity and momentum distributions.

Findings

Charged particle multiplicity distribution fitted with KNO scaling.

Observed stronger scaling violations in gluon jets compared to quark jets.

Results support the hypothesis that gluon jet fragmentation functions exhibit more significant scaling violations.

Abstract

In electron positron annihilation, changing quarks into the final hadron states is being described by fragmentation function. Based on the scaling hypothesis, this function will be independent from the center of mass energy. Gluon radiation violates the scaling feature. Transverse momentum distribution plays an important role in scaling violation of fragmentation functions. In this article, by the use of data resulted from the annihilation process of electron positron in AMY detector at 60 GeV center of mass energy, first, charged particles multiplicity distribution will be obtained and it will be fitted with the KNO scaling. Furthermore, momentum spectra of charged particles and momentum distribution respect to the jet axis will be obtained. Then, the results will be compared regarding the different models of QCD; as well, the distribution of fragmentation functions and scaling violations will be studied. It is being expected that the scaling violations of the fragmentation functions of gluon jet are stronger to the quark one. One of the reasons for such case is that splitting function of jet is larger than splitting function of gluon.