Testing the Inverted Neutrino Mass Ordering with Neutrinoless Double-Beta Decay

Abstract

We quantify the extent to which future experiments will test the existence of neutrinoless double-𝛽 decay mediated by light neutrinos with inverted-ordered masses. While it remains difficult to compare measurements performed with different isotopes, we find that future searches will fully test the inverted-ordering scenario, as a global, multi-isotope endeavor. They will also test other possible mechanisms driving the decay, including a large uncharted region of the allowed parameter space assuming that neutrino masses follow the normal ordering.