Global analysis of hadron-production data in e^+ e^- annihilation for determining fragmentation functions

TL;DR

This paper performs a comprehensive global analysis of hadron-production data in electron-positron annihilation to determine fragmentation functions for pions, kaons, and nucleons, including uncertainty estimates and implications for exotic hadron searches.

Contribution

It introduces the first uncertainty estimates for fragmentation functions and explores their application in identifying the internal structure of exotic hadrons like $f_0(980)$.

Findings

Light-quark and gluon fragmentation functions have large uncertainties.

Uncertainty estimates are crucial for heavy-ion collision and lepton scattering analyses.

Differences in favored and disfavored fragmentation functions can reveal exotic hadron structures.

Abstract

Fragmentation functions of pion, kaon, and nucleon are determined by global analyses of hadron-production data in $e^+e^-$ annihilation. It is particularly important that uncertainties of the fragmentation functions are estimated for the first time. We found that light-quark and gluon fragmentation functions have large uncertainties, so that one should be careful in using these functions for hadron-production processes in heavy-ion collisions and lepton scattering. The analysis is extended to possible exotic hadron search by fragmentation functions. We found that internal structure of $f_0 (980)$, such as $s\bar s$ or tetraquark configuration, can be determined by noting differences between favored and disfavored fragmentation functions.