First global QCD analysis of charged hadron fragmentation functions and their uncertainties at next-to-next-to-leading order

TL;DR

This paper presents the first comprehensive global analysis of charged hadron fragmentation functions at NNLO accuracy, improving data description and reducing uncertainties in QCD predictions for electron-positron annihilation processes.

Contribution

It introduces the SGK18 fragmentation functions derived from a NNLO QCD analysis, incorporating uncertainty estimation and comparison with existing results.

Findings

SGK18 FFs agree well with experimental data

NNLO corrections improve theoretical predictions

Uncertainties are reduced at NNLO

Abstract

In this paper, we present ${\tt SGK18}$ FFs, a first global QCD analysis of parton-to-{\it unidentified} charged hadrons fragmentation functions (FFs) at next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. This analysis is based on single-inclusive charged hadron production in electron-positron ($e^-e^+$) annihilation. The uncertainties in the extraction of ${\tt SGK18}$ FFs as well as the corresponding observables are estimated using the "Hessian" technique. We study the quality of the {\tt SGK18} FFs determined in this analysis by comparing with the recent results in literature. We also show how {\tt SGK18} FFs results describe the available data for single-inclusive unidentified charged hadron production in $e^-e^+$ annihilation. We demonstrate that the theoretical uncertainties due to the variation of the renormalization and factorization scales improve when NNLO QCD corrections are considered. We find that the resulting {\tt SGK18} FFs are in good agreement with all data analyzed and the inclusion of NNLO corrections tends to improve the data description with somewhat smaller uncertainty.