Physics beyond the Standard Model involving lepton number violation caused by a purported Majorana fermion is required to explain how this effect can occur without emitting a neutrino.
The integrals for the phase-space function describing this phenomenon can be written in a closed form by using the Primakoff-Rosen approximation, which yields the result that the phase-space function is independent of charge. There may be multiple possible internal mechanisms for this phenomenon, according to Schechter and Valle's "black box theorem." The GERDA and KamLAND-Zen experiments are attempting to observe this effect using germanium-76 and xenon-136, respectively; those nuclei are useful for observing this effect since the pairing force makes them exceptionally stable. Physics beyond the Standard Model involving lepton number violation caused by a purported Majorana fermion is required to explain how this effect can occur without emitting a neutrino. For 10 points, name this process in which two neutrons are transformed into two protons and two electrons.
The integrals for the phase-space function describing this phenomenon can be written in a closed form by using the Primakoff-Rosen approximation, which yields the result that the phase-space function is independent of charge.
neutrinoless double beta decay [prompt on beta decay or neutrinoless beta decay]