  We consider the singlet Majoron model with softly broken lepton number. This
model contains three right-handed neutrinos and a singlet scalar besides the
standard model fields. The real part of the singlet scalar develops a vacuum
expectation value to generate the lepton number violation for seesaw and
leptogenesis. The imaginary part of the singlet scalar becomes a massive
pseudo-Majoron to be a dark matter candidate with testability by colliders,
direct detection experiments and neutrino observations.
