What a direct neutrino mass measurement might teach us about the dark sector

Searches for Dark Matter suggest that it couples to ordinary matter only very weakly and possibly only through the Higgs or other scalar bosons. On the other hand, neutrinos might not couple to the Higgs boson directly, but only through a loop of Dark Matter particles, which would naturally explain the small neutrino masses. We demonstrate that current experimental constraints on such a ``scotogenic’’ scenario allow to make the linear dependence of the lightest neutrino mass on the dark sector-Higgs coupling explicit, so that a measurement by the KATRIN experiment would directly determine its value.