Model Independent Constraints of the Averaged Neutrino Masses Revisited

Abstract

Averaged neutrino masses defined by m ν ab ≡ 3 j=1 U aj U bj m j (a, b = e, µ, τ ) are reanalyzed using up-to-date observed MNS parameters and neutrino masses by the neutrino oscillation experiments together with the cosmological constraint on neutrino masses. The values of m ν ab are model-independently evaluated in terms of effective neutrino mass defined by m ν ≡ |U ej | 2 m 2 j 1/2 which is observable in the single beta decay. We obtain lower bound for m ν ee in the inverted hierarchy(IH) case, 17 meV ≤ m ν ee and one for m ν τ µ in the normal hierarchy(NH) case, 5 meV ≤ m ν τ µ . We also obtain that all the averaged masses m ν ab have upper bounds which are at most 80 meV.