Constraints on neutrino mass ordering and degeneracy from Planck and neutrino-less double beta decay

TL;DR

This paper uses Planck cosmic microwave background data and neutrino-less double beta decay results to constrain neutrino mass ordering and degeneracy, showing significant limits on degeneracy and potential to distinguish mass hierarchy.

Contribution

It provides new cosmological constraints on neutrino mass degeneracy and explores how combining different experiments can determine neutrino mass ordering.

Findings

95% CL rejects >85% degeneracy in normal hierarchy

Limits on degeneracy for inverted hierarchy

Potential to distinguish mass ordering with combined data

Abstract

We investigate constraints on neutrino mass ordering and degeneracy by considering the first cosmological result based on Planck measurements of the cosmic microwave background. It is shown that the result at 95% CL rejects a neutrino mass degeneracy larger than 85% (82.5%) for the normal (inverted) hierarchical case. We can also find some regions where the neutrino mass ordering will be able to be distinguished by combining a value of sum of the neutrino masses with an effective neutrino mass determined by neutrino-less double beta decay experiments.