Prospects for Finding Sterile Neutrino Dark Matter at KATRIN

Understand

We discuss under what circumstances a signal in upcoming laboratory searches for keV-scale sterile neutrinos would be compatible with those particles being a sizable part or all of dark matter.

• In the parameter space that will be experimentally accessible by KATRIN/TRISTAN, strong X-ray limits need to be relaxed and dark matter overproduction needs to be avoided.
• We discuss postponing the dark matter production to lower temperatures, a reduced sterile neutrino contribution to dark matter, and a reduction of the branching ratio in photons and active neutrinos through cancellation with a new physics diagram.
• Both the Dodelson-Widrow and the Shi-Fuller mechanisms for sterile neutrino dark matter production are considered.