2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47341We propose a modification of the mechanism of charmed quarks fragmentation into $D$ mesons in hadronic collisions. It is shown that the distinction in valence quark distributions in the initial $π^{\pm}$ and $K^{\pm}$ mesons leads to different inclusive spectra of $D$ and $D_s$ mesons produced in $π^{\pm}$ and $K^{\pm}$ beams.18 pages, LaTeX, epsfig, 5 figuresHigh Energy Physics - Phenomenologytext