Global analysis of fragmentation functions for pions and kaons and their uncertainties
D. de Florian, R. Sassot, M. Stratmann
TL;DR
This work performs a comprehensive NLO global analysis of pion and kaon fragmentation functions by incorporating charged-hadron data to disentangle quark and antiquark fragmentation. It combines e+e- annihilation, SIDIS, and hadron-hadron data, utilizing Mellin-transform techniques for fast, exact cross-section calculations and the Lagrange multiplier method to quantify FF uncertainties. The study yields well-constrained, flavor-separated FFs with quantified uncertainties (roughly 3% for favored and 10–20% for unfavored channels) and demonstrates meaningful synergy between diverse datasets, reinforcing the universality and factorization of FFs. The results broaden the kinematic coverage and improve upon previous extractions, providing robust inputs for precision QCD phenomenology involving identified pions and kaons.
Abstract
We present new sets of pion and kaon fragmentation functions obtained in NLO combined analyses of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and deep-inelastic lepton-proton scattering with either pions or kaons identified in the final state. At variance with all previous fits, the present analyses take into account data where hadrons of different electrical charge are identified, which allow to discriminate quark from anti-quark fragmentation functions without the need of non trivial flavor symmetry assumptions. The resulting sets are in good agreement with all data analyzed, which cover a much wider kinematical range than in previous fits. An extensive use of the Lagrange multiplier technique is made in order to assess the uncertainties in the extraction of the fragmentation functions and the synergy from the complementary data sets in our global analysis.