2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45731The observed features of $ψ'$ to $J/ψ$ suppression in $pA$ and nucleus-nucleus collisions can be explained in terms of a two-component absorption model. For the hard component of the absorption due to the interaction of the produced $c\bar c$ systems with baryons at high relative energies, the absorption cross sections are insensitive to the radii of the $c\bar c$ systems, as described by the Additive Quark Model. For the soft component due to the low energy $c \bar c$ interactions with soft particles produced by other baryon-baryon collisions, the absorption cross sections are greater for $ψ'$ than for $J/ψ$, because the breakup threshold for $ψ'$ is much smaller than for $ψ$.Based on a talk presented at International Nuclear Physics Conference '95, Beijing, China, 5 pages (Latex), 2 uuencoded ps figuresHigh Energy Physics - Phenomenologytext