keV sterile neutrino with large mixing angle is still alive

¹ Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312, Russia
² Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia

^* e-mail: chudy@ms2.inr.ac.ru

Published online: 31 October 2018

Abstract

We study production of keV scale sterile neutrinos with large mixing with the Standard Model sector [1]. Conventional mechanism of sterile neutrino generation in the early Universe leads to overproduction of the Dark Matter and strong X-ray signal from sterile neutrino decay. It makes anticipated groundbased experiments on direct searches of sterile-active mixing unfeasible. We argue that for models with a hidden sector coupled to the sterile neutrinos cosmological and astrophysical constraints can be significantly alleviated. In developed scenario a phase transition in the hidden sector modifies the standard oscillation picture and leads to significantly larger mixing angles, thus opening new perspectives for future neutrino experiments such as Troitsk v-mass and KATRIN.

This work was made in collaboration with Fedor Bezrukov and Dmitry Gorbunov.