2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/118630This paper has been withdrawn by the authors due to missing references to earlier work and an error in the interpretation of Figures 2 and 3. A corrected version is in preparation.This paper has been withdrawnAstrophysicsWhen Do Ultra-relativistic Shocks Make Energetic Particle Populations?text