Abstract
Abstract
Right-handed neutrinos (v
R
) offer an intriguing
portal to new physics in hidden sectors where dark matter (DM) may
reside. In this work, we delve into the simplest hidden sector involving
only a real scalar exclusively coupled to v
R
, referred to
as the v
R
-philic scalar. We investigate the viability of the
v
R
-philic scalar to serve as a DM candidate, under the constraint
that the coupling of v
R
to the standard model is determined
by the seesaw relation and is responsible for the observed DM abundance.
By analyzing the DM decay channels and solving Boltzmann equations,
we identify the viable parameter space. In particular, our study reveals
a lower bound (2.6 × 105 GeV) on the mass of v
R
for
the v
R
-philic scalar to be DM. The DM mass may vary from sub-MeV
to sub-GeV. Within the viable parameter space, monochromatic neutrino
lines from DM decay can be an important signal for DM indirect detection.