Importance of Fragmentation Functions in Determining Polarized Parton Densities

TL;DR

This paper derives new fragmentation functions from experimental data and examines their impact on polarized parton density determinations, highlighting significant differences from previous models and their influence on polarized PDFs.

Contribution

The study introduces updated fragmentation functions based on recent data and analyzes their effect on polarized parton densities, revealing notable differences from earlier models.

Findings

New kaon fragmentation functions differ significantly from previous models.

Polarized PDFs are sensitive to the choice of fragmentation functions.

Updated FFs influence the extraction of polarized parton densities.

Abstract

New fragmentation functions (FFs) are extracted from a NLO QCD fit to the preliminary COMPASS data on pion and kaon multiplicities. It is shown that the new kaon FFs are very different from those of De Florian at al. (DSS) and Hirai et al. (HKNS). The sensitivity of the extracted polarized PDFs to the new FFs is discussed.