Discovering neutrinoless double-beta decay in the era of precision neutrino cosmology

TL;DR

This paper assesses the likelihood of discovering neutrinoless double-beta decay through combined experiments, emphasizing the role of neutrino mass measurements from cosmology and nuclear uncertainties, and highlights the strong motivation for multi-isotope searches.

Contribution

It provides a comprehensive analysis of discovery probabilities considering neutrino mass scenarios, nuclear uncertainties, and cosmological data, advocating for a multi-isotope experimental approach.

Findings

Discovery probability varies from 0% to 80-90% depending on neutrino mass.

Cosmological measurements of neutrino mass significantly influence discovery prospects.

Combining data from different isotopes mitigates nuclear matrix element uncertainties.

Abstract

We evaluate the discovery probability of a combined analysis of proposed neutrinoless double-beta decay experiments in a scenario with normal ordered neutrino masses. The discovery probability strongly depends on the value of the lightest neutrino mass, ranging from zero in case of vanishing masses and up to 80-90\% for values just below the current constraints. We study the discovery probability in different scenarios, focusing on the exciting prospect in which cosmological surveys will measure the sum of neutrino masses. Uncertainties in nuclear matrix element calculations partially compensate each other when data from different isotopes are available. Although a discovery is not granted, the theoretical motivations for these searches and the presence of scenarios with high discovery probability strongly motivates the proposed international, multi-isotope experimental program.