PT Journal
AU Lattanzi, M
   Gerbino, M
   Freese, K
   Kane, G
   Valle, JWF
TI Cornering (quasi) degenerate neutrinos with cosmology
SO Journal of High Energy Physics
JI J. High Energy Phys.
PY 2020
BP 213
EP 24pp
VL 10
IS 10
DI 10.1007/JHEP10(2020)213
LA English
DE Cosmology of Theories beyond the SM; Neutrino Physics
AB In light of the improved sensitivities of cosmological observations, we examine the status of quasi-degenerate neutrino mass scenarios. Within the simplest extension of the standard cosmological model with massive neutrinos, we find that quasi-degenerate neutrinos are severely constrained by present cosmological data and neutrino oscillation experiments. We find that Planck 2018 observations of cosmic microwave background (CMB) anisotropies disfavour quasi-degenerate neutrino masses at 2.4 Gaussian sigma 's, while adding baryon acoustic oscillations (BAO) data brings the rejection to 5.9 sigma 's. The highest statistical significance with which one would be able to rule out quasi-degeneracy would arise if the sum of neutrino masses is Sigma m(v) = 60 meV (the minimum allowed by neutrino oscillation experiments); indeed a sensitivity of 15 meV, as expected from a combination of future cosmological probes, would further improve the rejection level up to 17 sigma. We discuss the robustness of these projections with respect to assumptions on the underlying cosmological model, and also compare them with bounds from beta decay endpoint and neutrinoless double beta decay studies.
ER