Global analysis for determining fragmentation functions and their uncertainties in light hadrons

TL;DR

This paper analyzes fragmentation functions for light hadrons using electron-positron data, emphasizing the importance of uncertainty estimation and comparing different analysis groups, with results showing large uncertainties at small Q^2 and improvements at NLO.

Contribution

It provides a comprehensive analysis of fragmentation functions for pions, kaons, and protons, including uncertainty estimation and a comparison across different groups, with a new code for calculations.

Findings

Gluon and light-quark functions have large uncertainties at small Q^2.

NLO uncertainties are significantly smaller than LO for pions and kaons.

Recent fragmentation functions are consistent within estimated uncertainties.

Abstract

Fragmentation functions are determined for the pion, kaon, and proton by analyzing charged-hadron production data in electron-positron annihilation. It is important that uncertainties of the determined fragmentation functions are estimated in this analysis. Analysis results indicate that gluon and light-quark functions have large uncertainties especially at small Q^2. We find that next-to-leading-order (NLO) uncertainties are significantly reduced in comparison with leading-order (LO) ones in the pion and kaon. The fragmentation functions are very different in various analysis groups. However, all the recent functions are roughly within the estimated uncertainties, which indicates that they are consistent with each other. We provide a code for calculating the fragmentation functions and their uncertainties at a given kinematical point of z and Q^2 by a user.