Neutrino oscillations and neutrinoless double-beta decay

TL;DR

This paper analyzes how neutrino mixing and mass hierarchy influence neutrinoless double-beta decay, establishing a lower bound on the effective Majorana mass and exploring implications for models with three or four neutrinos.

Contribution

It demonstrates that solar neutrino data impose a lower bound on the effective Majorana mass in neutrinoless double-beta decay under natural assumptions, and discusses four-neutrino schemes.

Findings

Solar neutrino experiments imply a lower bound on Majorana mass.

Four-neutrino mixing schemes are favored by data.

Natural assumptions exclude fine-tuned cancellations.

Abstract

We consider the scheme with mixing of three neutrinos and a mass hierarchy. We shown that, under the natural assumptions that massive neutrinos are Majorana particles and there are no unlikely fine-tuned cancellations among the contributions of the different neutrino masses, the results of solar neutrino experiments imply a lower bound for the effective Majorana mass in neutrinoless double-beta decay. We also discuss briefly neutrinoless double-beta decay in schemes with mixing of four neutrinos. We show that one of them is favored by the data.