Using the Drell-Levy-Yan relation, the pion and kaon elementary fragmentation functions (EFFs) are obtained from their hadron-scale parton distribution functions (DFs). These EFFs serve as driving terms in the hadron cascade equations, whose solution yields the complete array of hadron-scale fragmentation functions (FFs) for pion and kaon production in high energy reactions. Evolved to experimental scales, the continuum Schwinger function methods (CSMs) predictions satisfy QCD endpoint behavior: nonsinglet FFs vanish at z=0, singlet FFs diverge faster than 1/z. Jet multiplicity predictions reveal SU(3) symmetry breaking in the charged/neutral kaon ratio, decreasing with energy, and show the pion/kaon ratio in e+e− collisions asymptotes to a mass-independent value.
@article{arxiv.2603.22976,
title = {Pion and Kaon Fragmentation Functions from Continuum Schwinger Function Methods},
author = {Hui-Yu Xing},
journal= {arXiv preprint arXiv:2603.22976},
year = {2026}
}