On the MSW neutrino mixing effects in atomic weak interactions and double beta decays

TL;DR

This paper examines whether high electron densities inside atomic nuclei influence neutrino mixing effects and related phenomena like double beta decay, concluding that standard formulas remain valid but highlighting potential impacts on other observables.

Contribution

It investigates the impact of atomic-scale electron densities on neutrino mixing and double beta decay, an area previously considered only in bulk matter, and finds standard results still hold.

Findings

Standard double beta decay formulas are unaffected by atomic electron densities.

Neutrino mixing effects inside nuclei may influence other rare decay processes.

The study opens possibilities for new observables affected by atomic-scale neutrino mixing.

Abstract

Matter effects on the mixing of the neutrinos mass eigenstates, also know as the Mikheyev-Smirnov-Wolfenstein effect, seem to be well established in describing the propagation of the neutrino from the source to detecting devices. These effects were mostly considered in bulk matter, but not inside the atoms. Here we consider the effect of the high electron densities existing in the atomic nuclei. We investigate if these effects can affect the known neutrino phenomenology. It was reported that the mixing of the neutrino in high density matter, such as inside a supernova, can affect the Majoron decay probabilities. We investigate if the neutrino mixing effects in the high electron density inside the atomic nuclei can change the neutrinoless double beta decay half-life formula. In both cases we found that the standard results stand. The results look simple, but the road to them is complex and it opens the possibility that the neutrino mixing in atomic nuclei may affect other observables, such as the neutrinoless double beta Majoron decays.