2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/181768The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty.16 pages, 2 figures, RevTeX, Refs. updated, further typos corrected, to appear in EPJCHigh Energy Physics - Phenomenologytext