Double Beta Decay

Abstract

Double beta (ββ) decay is a rare transition between two nuclei with
\nthe same mass number that changes the nuclear charge number by two
\nunits. It has been long recognized as a powerful tool for the study of
\nlepton conservation in general and of neutrino properties in particular.
\nBecause the lifetimes of ββ decay are so long, the experimental study
\nof ββ decay is particularly challenging and has spawned a whole field
\nof experiments requiring very low background.