Inclusive light-hadron production in photon-photon collisions at NLO

I review a recent global analysis of inclusive single-charged-hadron production in high-energy colliding-beam experiments. In the framework of the parton model of quantum chromodynamics at next-to-leading order (NLO), fragmentation functions (FFs) for charged pions, charged kaons, and (anti) protons are extracted from experimental data of e(+)e(-) annihilation at the Z-boson resonance and at centre-of-mass energy roots = 29 GeV. Comparisons of gammagamma data from LEP2 with the corresponding NLO predictions allow us to test the universality of the FFs predicted by the factorization theorem. Possible modifications of the theory in view of the found discrepancy of the NLO predictions with recent data from the L3 Collaboration are shortly discussed.