2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46201The exchange of massless neutrinos between heavy fermions (e.g. $e,p,n$) gives rise to a long-range 2-body force. It is shown that the analogous many-body force can lead to an unphysically large energy density in white dwarfs and neutron stars. To reduce the energy density to a physically acceptable value, the neutrino must have a {\it minimum mass}, which is approximately $0.4\;eV/c^2$. Some recent questions relating to the derivation of this bound are also discussed.4 pages; Moriond ProceedingsHigh Energy Physics - Phenomenologytext