  We study the prospect of heavy singlet neutrinos as a dark matter (DM)
candidate within a neutrinophilic U(1) model, where the Standard Model (SM) is
extended with a U(1) gauge symmetry, and neutrino mass and oscillation
parameters are explained through an inverse see-saw mechanism. The lightest of
the heavy neutrinos plays the role of the DM while the newly introduced scalars
and the extra gauge boson Z' act as mediators between the dark sector and the
SM sector. We show the range of model parameters where this DM candidate can be
accommodated in the Weakly Interacting Massive Particle (WIMP) or Feebly
Interacting Massive Particle (FIMP) scenario. The observed DM relic density is
achieved via the new gauge boson and singlet scalar portals in the WIMP
scenario whereas within the FIMP scenario, these two particles assume a
distinct yet pivotal role in generating the observed relic density of dark
matter.
