Global constraints on absolute neutrino masses and their ordering

Within the standard three-neutrino framework, the absolute neutrino masses and their ordering (eithernormal, NO, or inverted, IO) are currently unknown. However, the combination of current data comingfrom oscillation experiments, neutrinoless double beta (0νββ) decay searches, and cosmological surveys,can provide interesting constraints for such unknowns in the sub-eV mass range, down toOð10−1ÞeV insome cases. We discuss current limits on absolute neutrino mass observables by performing a global dataanalysis that includes the latest results from oscillation experiments,0νββdecay bounds from theKamLAND-Zen experiment, and constraints from representative combinations of Planck measurementsand other cosmological data sets. In general, NO appears to be somewhat favored with respect to IO at thelevel of∼2σ, mainly by neutrino oscillation data (especially atmospheric), corroborated by cosmologicaldata in some cases. Detailed constraints are obtained via theχ2method, by expanding the parameter spaceeither around separate minima in NO and IO or around the absolute minimum in any ordering. Implicationsfor upcoming oscillation and nonoscillation neutrino experiments, includingβ-decay searches, are alsodiscussed