Strengthening the bound on the mass of the lightest neutrino with terrestrial and cosmological experiments

We determine the upper limit on the mass of the lightest neutrino from the most robust recent cosmological and terrestrial data. Marginalizing over possible effective relativistic degrees of freedom at early times (N-eff) and assuming normal mass ordering, the mass of the lightest neutrino is less than 0.037 eVat 95% confidence; with inverted ordering, the bound is 0.042 eV. These results improve upon the strength and robustness of other recent limits and constrain the mass of the lightest neutrino to be barely larger than the largest mass splitting. We show the impacts of realistic mass models and different sources of N-eff.

Automated summary

The upper limit on the mass of the lightest neutrino has been determined using recent cosmological and terrestrial data. These results are more robust than previous limits and constrain the mass of the lightest neutrino to be barely larger than the largest mass splitting. Impacts of realistic mass models and different sources of N-eff have been shown.