Double Beta-Minus Decay
Double beta-minus decay is a very rare nuclear decay process[1] in which two neutrons change into two protons and two electrons are emitted.
There are two types of double beta-minus decay. The first is ordinary double beta-minus decay. In this type of decay, two electrons are emitted, and two electron antineutrinos are emitted as well. It can be thought of as just two single beta-minus decays happening simultaneously. The second is neutrinoless double beta-minus decay. In this type of decay, two electrons are emitted, but no neutrinos are emitted[1]. This would only be possible if a neutrino were its own antiparticle – that is, if it were a Majorana particle[1]. So far, neutrinoless double beta decay remains theoretical, and has not been observed experimentally[2].
An Example of Double Beta-Minus Decay
Calcium-48 is an isotope of calcium that can undergo double beta-minus decay to titanium-48. The nuclear equation below represents this process.
Two neutrons in the calcium nucleus change into protons, increasing the atomic number by 2. The total number of nucleons stays the same, so the mass number remains 48. 2 electrons and 2 electron antineutrinos are emitted.
References
- ^ , Neutrinoless Double-Beta Decay, Advances in High Energy Physics 2012 (1). https://onlinelibrary.wiley.com/doi/abs/10.1155/2012/857016
- ^ , Measurement of the double-beta decay half-life and search for the neutrinoless double-beta decay of $^48 Ca$ with the NEMO-3 detector, Physical Review D 93 (11). http://dx.doi.org/10.1103/PhysRevD.93.112008