Revision 1

Accepted · first revision · record

Title: Cosmological measurement of the neutrino mass sum to 0.015 eV
Plain: Cosmology can weigh neutrinos because heavier neutrinos smooth out the clumping of matter. The task is to measure the total mass with cosmological data, not just bound it.
Precise: Measure sum $m_\nu$ with uncertainty $\sigma \le 0.015\,\mathrm{eV}$ from CMB lensing, galaxy clustering and BAO, with the reionization optical depth $\tau$ measured independently to $\sigma(\tau) \sim 0.002$. An answer is a value that also discriminates normal from inverted ordering.
Settled by: Simons Observatory and LiteBIRD-era CMB lensing and large-scale polarization combined with final DESI and Euclid.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: open
Status note: (empty)
Posed since: (empty)