Making large neutrino mass consistent with cosmology

by Thomas Schwetz-Mangold (KIT)

Thursday 6 Jun 2024, 15:00 → 16:30 Europe/Berlin

seminar room 3 (bldg. 1b)

Neutrino mass constraints from cosmology are becoming increasingly tight, approaching the minimal values predicted by oscillation experiments. This may lead to a conflict in the near future and furthermore, makes direct neutrino mass detection unlikely. We discuss a scenario, which allows relatively large neutrino masses in agreement with cosmology: If neutrinos come into equilibrium with massless dark-sector particles between BBN and recombinations, the energy density in neutrinos is diluted while keeping N_eff approximately constant, which effectively relaxes neutrino mass bounds. We present a simple seesaw model for neutrino mass, based on a dark U(1) gauge symmetry, where this mechanism can be implemented.