Higher Reionization Optical Depth Yields Tentative Neutrino Mass Detection, Reduces Cosmological Tensions

Researchers reported a tentative detection of neutrino mass after adopting a higher optical depth to reionization in their cosmological analysis, according to Sciencecast. The study employed a prior of τ = 0. 11 ± 0. 006, which is larger than the values typically used in ΛCDM fits.

With this elevated τ, the analysis yielded a roughly 2σ indication of a total neutrino mass of about 0. 1 eV. The higher optical depth also brought early-Universe CMB measurements into closer alignment with late-time observations of the Hubble constant and the dark-energy equation of state. The authors noted that forthcoming CMB polarization experiments could test the validity of the increased τ prior.