2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194681The quality of the narrow-width approximation is examined for partonic and convolved cross sections of sample processes. By comparison with accurate predictions significant limitations are revealed.4 pages, 10 figures; refs. reordered, version to be published in Phys. Lett. BHigh Energy Physics - Phenomenologytext