A New Cosmology Based Neutrino Mass Estimate

For the flat ΛCDM model with the sum of neutrino mass ∑mν free, combining the DESI and CMB data yields an upper limit ∑mν<0.072 (0.113) eV at 95% confidence for a ∑mν>0 (∑mν>0.059) eV prior. These neutrino-mass constraints are substantially relaxed in models beyond ΛCDM.

From arXiv:2404.0300.

This suggests that a near zero lightest neutrino mass is the best fit value, that a one sigma range for the lightest neutrino mass in a normal hierarchy, is about 0-8.7 meV and that a two sigma range for the lightest neutrino mass in a normal hierarchy is about 0-17.3 meV. It also disfavors, but not decisively, an inverted neutrino mass hierarchy.

The merely non-zero Bayesian prior for the sum of the three neutrino masses is contrary to the whole point of using Bayesian statistics, and should just be ignored as meaningless.