Calculating Kaon Fragmentation Functions from NJL-Jet Model

TL;DR

This paper extends the NJL-Jet model to include strange quarks, calculating kaon fragmentation functions that qualitatively agree with empirical data, aiding semi-inclusive data analysis.

Contribution

The study introduces strange quark effects into the NJL-Jet model for fragmentation functions, providing a more comprehensive theoretical framework.

Findings

Kaon fragmentation functions qualitatively match empirical parameterizations.

Unfavored strange quark fragmentation to pions is comparable to unfavored light quark fragmentation.

Model satisfies momentum and isospin sum rules without ad hoc parameters.

Abstract

The Nambu--Jona-Lasinio (NJL) - Jet model provides a sound framework for calculating the fragmentation functions in an effective chiral quark theory, where the momentum and isospin sum rules are satisfied without the introduction of ad hoc parameters. Earlier studies of the pion fragmentation functions using the NJL model within this framework showed qualitative agreement with the empirical parameterizations. Here we extend the NJL-Jet model by including the strange quark. The corrections to the pion fragmentation functions and corresponding kaon fragmentation functions are calculated using the elementary quark to quark-meson fragmentation functions from NJL. The results for the kaon fragmentation functions exhibit a qualitative agreement with the empirical parameterizations, while the unfavored strange quark fragmentation to pions is shown to be of the same order of magnitude as the unfavored light quark's. The results of these studies are expected to provide important guidance for the analysis of a large variety of semi-inclusive data.