The contribution of light Majorana neutrinos to neutrinoless double beta decay and cosmology

TL;DR

This paper discusses how recent cosmological bounds on neutrino masses suggest that detecting neutrinoless double beta decay may be more challenging than previously thought, especially if the normal hierarchy is confirmed.

Contribution

It links cosmological neutrino mass constraints with the potential detectability of neutrinoless double beta decay, highlighting implications for future experiments.

Findings

Cosmological data suggests lightest neutrino mass < 84 meV at 1σ.

Preferred neutrino mass hierarchy is normal.

Effective Majorana mass likely below 75 meV at 3σ.

Abstract

Cosmology is making impressive progress and it is producing stringent bounds on the sum of the neutrino masses {\Sigma}, a parameter of great importance for the current laboratory experiments. In this letter, we exploit the potential relevance of the analysis of Palanque-Delabrouille et al. [JCAP 1502, 045 (2015)] to the neutrinoless double beta decay (0{\nu}{\beta}{\beta}) search. This analysis indicates small values for the lightest neutrino mass, since the authors find {\Sigma} < 84 meV at 1{\sigma} C. L., and provides a 1{\sigma} preference for the normal hierarchy. The allowed values for the Majorana effective mass, probed by 0{\nu}{\beta}{\beta}, turn out to be < 75meV at 3{\sigma}C.L. and lower down to less than 20meV at 1{\sigma}C.L.. If this indication is confirmed, the impact on the 0{\nu}{\beta}{\beta} experiments will be tremendous since the possibility of detecting a signal will be out of the reach of the next generation of experiments.