Speaker
Description
The sterile neutrino is a well motivated Dark Matter candidate, but the minimal Dodelson-Widrow production mechanism has been experimentally excluded by searches for X-rays. We are presenting an extension, in which DM consists of sterile neutrinos which are charged under a broken $U(1)'$ symmetry. As long as one sterile neutrino is neutral under $U(1)'$, they will mix with the SM neutrino through a seesaw mechanism. In addition to generating neutrino masses, the mixing will naturally add a channel triggering exponential growth of the Dark Matter abundance in the early universe, through the process $\nu_s \nu_{SM} \to \nu_s \nu_s$. With an initial abundance generated by Dodelson-Widrow, we show that this mechanism opens up the parameter space, in mass and mixing angle, where sterile neutrinos can make up all of the Dark Matter. We also find that the available parameter space is bounded from all sides by limits from DM self-interactions, X-ray and Lyman-$\alpha$ searches.
| Main Contribution topic | Theory / Phenomenology |
|---|---|
| Secondary contribution topic | Axion / Sterile |