  In some dark matter models, the coupling of the dark matter particle to the
standard model Higgs determines the dark matter relic density while it is also
consistent with dark matter direct detection experiments. On the other hand,
the seesaw for generating the neutrino masses probably arises from a
spontaneous symmetry breaking of global lepton number. The dark matter particle
thus can significantly annihilate into massless Majorons when the lepton number
breaking scale and hence the seesaw scale is near the electroweak scale. This
leads to an interesting interplay between neutrino physics and dark matter
physics and the annihilation mode has an interesting implication on dark matter
searches.
