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Abstract

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. As a final exotic example, potential
consequences of CPT violation are discussed.