Neutrinoless double-beta decay with three or four neutrino mixing

TL;DR

This paper analyzes how different neutrino mixing schemes, including three and four neutrino models, impose lower bounds on the effective Majorana mass relevant for neutrinoless double-beta decay, considering experimental and cosmological constraints.

Contribution

It demonstrates that only one four-neutrino scheme aligns with all experimental data and provides lower bounds on the Majorana mass based on neutrino mixing assumptions.

Findings

Lower bound on Majorana mass from solar neutrino data

Compatibility of one four-neutrino scheme with experimental and cosmological data

LSND results imply a lower bound on neutrinoless double-beta decay mass

Abstract

Considering the scheme with mixing of three neutrinos and a mass hierarchy that can accommodate the results of solar and atmospheric neutrino experiments, it is shown that the results of solar neutrino experiments imply a lower bound for the effective Majorana mass in neutrinoless double-beta decay, 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. Considering the four-neutrino schemes that can accommodate also the results of the LSND experiment, it is shown that only one of them is compatible with the results of neutrinoless double-beta decay experiments and with the measurement of the abundances of primordial elements produced in Big-Bang Nucleosynthesis. It is shown that in this scheme, under the assumptions that massive neutrinos are Majorana particles and there are no cancellations among the contributions of the different neutrino masses, the results of the LSND experiment imply a lower bound for the effective Majorana mass in neutrinoless double-beta decay.