Fragmentation Functions of Charged Hadrons at Next-to-Next-to-Leading Order and Constraints on the Proton Parton Distribution Functions

TL;DR

This paper provides the first comprehensive global analysis of charged hadron fragmentation functions at NNLO in QCD, using diverse experimental data, and explores their influence on proton parton distribution functions, especially strange quark asymmetry.

Contribution

It introduces the first NNLO global analysis of light charged hadron fragmentation functions incorporating multiple data sources and examines their impact on constraining proton PDFs.

Findings

Fragmentation functions are successfully extracted at NNLO.

Data favor a reduced strange quark asymmetry in the proton.

Collinear factorization holds well at high hadron momenta.

Abstract

We present the first global analysis of fragmentation functions (FFs) for light charged hadrons ($\pi^{\pm}$, $K^{\pm}$) at full next-to-next-to-leading order in Quantum Chromodynamics (QCD), incorporating world data from both single-inclusive electron-positron annihilation and semi-inclusive deep-inelastic scattering. The collinear factorization has been tested with low-momentum-transfer data and has demonstrated success at high hadron momenta. Additionally, we study the impact of current global data on hadron production to the parton distribution functions (PDFs), and find they favor a reduced asymmetry in the strange (anti-) quark PDFs, as compared to the asymmetry predicted by state-of-the-art PDFs derived from inclusive data.