Abstract

In this talk, I will present recent work about reconstructing the neutrino mass as a function of redshift z. I will demonstrate that current cosmological data are consistent with a constant neutrino mass in time, with a larger bound on the neutrino mass at low redshifts coinciding with the onset of dark energy domination, of 1.38 eV (95% CL). This result can be explained either by the well-known degeneracy between ∑m_\nu and the dark energy density at low redshifts, or by models in which neutrino masses are generated very late in the Universe. Futhermore, I will explain how the results of the reconstruction can be converted into cosmological limits for models with post-recombination neutrino decay. In this case, we find an upper bound of 0.18 eV (95% CL), which is below the sensitivity of the KATRIN experiment. Thus, a neutrino mass discovery by KATRIN would hint towards models predicting both post-recombination neutrino mass generation and subsequent relic neutrino annihilation. This is joint work with Lena Funcke, Matthias Löffler and Erminia Calabrese.