The influence of fragmentation models in the production of hadron jets in electron–positron annihilation

[摘要] The analysis of electron–positron annihilations to hadrons at high energies shows that apart from two-jet events, there are also signs of three-jet events which are interpreted according to the QCD, as a gluon radiated by a quark. In this paper, we investigate the fragmentation of quarks and gluons to hadron jets. We show that gluon jets have a higher multiplicity compared to quark jets of the same energy. Furthermore, inclusion of different flavours in the distributions shows that quark jets are flavour-dependent, but gluon jets are not. The differences between quark and gluon jets also manifest themselves in the fragmentation functions. We observe that the fragmentation for gluon jet is softer than that for quark jet, because the radiation of soft gluons is larger for gluon jetsand that gluon cannot be present as a valence parton inside a produced hadron. We provide possible explanations for these features in this paper.

[学科分类] 物理（综合）

[关键词] Annihilation;hadron jets;quark;gluon.