Dark sector to the rescue of large cosmological neutrino mass

by Mr Drona Vatsyayan (Valencia U.)

Thursday 22 May 2025, 16:00 → 17:30 Asia/Seoul

Zoom

Title: Dark sector to the rescue of large cosmological neutrino mass

Speaker: Drona Vatsyayan (Valencia U.)

Abstract: The bound on the sum of neutrino masses from various cosmological surveys are increasingly becoming stronger, and are in significant tension with those obtained from the oscillation data and terrestrial experiments searching for the absolute neutrino mass scale. In this talk, I will discuss several non standard cosmology scenarios called large neutrino mass cosmologies that allow for relaxing the bound from cosmology and reconcile it with the ones from laboratory. In particular, I will present an extended seesaw model which generates active neutrino masses via the usual type-I seesaw and leads to a large number of massless fermions as well as a sterile neutrino dark matter (DM) candidate in the O(10 − 100) keV mass range. The dark sector comes into thermal equilibrium with Standard Model neutrinos after neutrino decoupling and before recombination via a U(1) gauge interaction in the dark sector. This suppresses the abundance of active neutrinos and therefore reconciles sizeable neutrino masses with
cosmology. Our scenario predicts a slight increase in the effective number of neutrino species Neff at recombination, potentially detectable by future CMB missions.

 

Zoom link: 

https://us06web.zoom.us/j/81891892372?pwd=IbHMUw3A3lhBeWaVY331DrSjCG0oG6.1

Zoom meeting ID: 818 9189 2372
Password: 401205