Neutrino Masses and Mass Hierarchy: Evidence for the Normal Hierarchy

Understand

The latest cosmological constraints on the sum of neutrino masses, in combination with the latest laboratory measurements on oscillations, provide ``decisive" Bayesian evidence for the normal neutrino mass hierarchy.

• We show that this result holds across very different prior alternatives by exploring two extremes on the range of prior choices.
• In fact, while the specific numerical value for the Evidence depends on the choice of prior, the Bayesian odds remain greater than 140:1 across very different prior choices.
• For Majorana neutrinos this has important implications for the upper limit of the neutrino-less double beta decay half life and thus for the technology and resources needed for future double beta decay experiments.