2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/216971We point out that the Pauli blocking of neutrinos by cosmological relic neutrinos can be a significant effect. For zero-energy neutrinos, the standard parameters for the neutrino background temperature and density give a suppression of approximately 1/2. We show the effect this has on three-body beta decays. The size of the effect is of the same order as the recently suggested neutrino capture on beta-decaying nuclei.4 pages, 2 figures, contribution to procedings of PANIC 2008High Energy Physics - PhenomenologyCosmology and Nongalactic AstrophysicsHigh Energy Physics - Experimenttext