Searching for dark matter sterile neutrinos in the laboratory

If the dark matter of the Universe is made of sterile neutrinos with mass in the keV region, it can be searched for with the help of x-ray satellites. We discuss the prospects of laboratory experiments that can be competitive and complementary to space missions. We argue that the detailed study of $\beta$ decays of tritium and other nuclei with the help of cold target recoil ion momentum spectroscopy can potentially enter into an interesting parameter range and even supersede the current astronomical bounds on the properties of the dark matter sterile neutrinos.

Figure 1

Constraints on the mixing angle $\theta$ of a sterile neutrino with an active neutrino from x-ray observations of large Magellanic clouds and the Milky Way by XMM-Newton and the Milky Way by HEAO-1 satellites and from kink searches in beta decay. The x-ray bound is in the assumption that sterile neutrinos constitute $p=100\%$ of the DM; for smaller $p$ the bound is relaxed accordingly. The boundaries of the parameter space accessible to $\beta$-decay experiments are shown for various values of the source temperature, kinematic cuts, and collected statistics.