Neutrino Mass Ordering

The problem Since 2016, a lot of authors tryed to extract information on the neutrino mass ordering using cosmological data, alone and in combination with neutrino oscillation constraints. One of the most debated topics regards the parameterization and the priors that should be used when describing the neutrino mass sector in such kind of analyses. Simpson et al. used logarithmic priors on the three neutrino masses (, , ) to describe the parameter space and found a strong preference for normal ordering which was never noticed in other analyses (see also Schwetz et al.). Neutrino oscillation data, however, are only sensitive to the squared-mass differences,Read More →

In this page we briefly resume the status of the mass ordering presented here and updated here. The results of the global analysis are here. Masses and ordering The neutrino masses can be ordered in two ways: normal ordering (NO): the lightest neutrino is , the one with the largest mixing with the electron neutrino flavor, and ; inverted ordering (IO): the lightest neutrino is , the one with the smallest mixing with the electron neutrino flavor, and . The mass ordering can be determined measuring the sign of or singling out each of the masses of the three neutrino mass eigenstates. Indirect constraints mayRead More →