2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190589We explore the feasibility of directly extracting the large-x valence d/u ratio through a measurement of pions in the current fragmentation region of semi-inclusive deep-inelastic scattering from protons.Discussion of factorization, higher twists added, version to appear in Phys. Lett. BHigh Energy Physics - PhenomenologyHigh Energy Physics - ExperimentNuclear Theorytext