Viable production mechanism of keV sterile neutrino with large mixing angle

Abstract

We study a model with a hidden sector coupled to keV scale sterile neutrinos. Due to nontrivial dynamics of this sector, the initially massless sterile neutrino acquires a nonzero mass at some temperature corresponding to the phase transition in the hidden sector. It shifts the onset of oscillations in plasma to later times, so that the final abundance of sterile neutrinos is strongly suppressed. We argue that in this model various cosmological and astrophysical bounds can be significantly alleviated opening new perspectives for ground-based experiments such as Troitsk ν-mass and KATRIN in the large mixing region.