Double Beta-Disintegration

Abstract

From the Fermi theory of $\beta$-disintegration the probability of simultaneous emission of two electrons (and two neutrinos) has been calculated. The result is that this process occurs sufficiently rarely to allow a half-life of over ${10}^{17}$ years for a nucleus, even if its isobar of atomic number different by 2 were more stable by 20 times the electron mass.