Properties of Gluon and Quark Jets

TL;DR

This paper reviews recent findings on gluon and quark jets, emphasizing energy scale effects, multiplicity ratios, and new algorithms for analyzing color flow in high-energy particle collisions.

Contribution

It introduces explicit energy scales for jets, analyzes multiplicity ratios, and presents novel algorithms for reconstructing color flow in jet events.

Findings

Multiplicity ratio in gluon/quark jets is less than the color factor ratio.

Scaling violation of fragmentation functions is proportional to color factors.

New algorithms enable detailed reconstruction of color flow.

Abstract

Recent developments and results on the comparison of gluon to quark jets are discussed. A most important topic is the introduction of explicit energy scales of the jets. The scaling violation of the fragmentation function and the increase of the multiplicity with scale is shown to be directly proportional to the corresponding gluon or quark colour factor. The ratio of the hadron multiplicity in gluon to quark jets is understood to be smaller than the colour factor ratio due to differences in the fragmentation of the leading quark or gluon. Novel algorithms to reconstruct the colour portraits or the colour flow of an event are presented.