Speaker
Description
A new tension is starting to emerge between the tight cosmological upper bounds on the total neutrino mass and the lower limits from oscillation data, with potentially far-reaching implications for cosmology and particle physics. Invisible neutrino decays provide a compelling particle physics scenario to understand such measurements. In this talk, I will present updated limits on a framework where neutrinos decay non-relativistically into dark radiation, showing that the mass bound from Planck 2018+DESI BAO DR2 is relaxed to 0.23 eV, in full agreement with oscillation data. I will also report the first late-time cosmological analysis of neutrino decays into lighter neutrinos in a manner consistent with the measured measured mass splittings, showing that this scenario marginally alleviates - or even tightens - the neutrino mass bounds. These results were possible thanks to new neural network emulators, which are ~200 times faster than the full Boltzmann solutions. Based on arXiv:2601.04312.