  The right-handed (RH) Higgs-induced neutrino mixing (RHINO) model explains
neutrino masses and origin of matter in the universe within a unified picture.
The mixing, effectively described by a dimension five operator, is responsible
both for the production of dark neutrinos, converting a small fraction of
seesaw neutrinos acting as source, and for their decays. We show that including
the production of source neutrinos from Higgs portal interactions, their
abundance can thermalise prior to the onset of source-dark neutrino
oscillations, resulting into an enhanced production of dark neutrinos that thus
can play the role of decaying dark matter (DM) for a much higher seesaw scale.
This can be above the sphaleron freeze-out temperature and as high as $\sim
100\,{\rm TeV}$, so that strong thermal resonant leptogenesis for the
generation of the matter-antimatter asymmetry is viable. We obtain a $\sim
1\,{\rm TeV}$--$1\,{\rm PeV}$ allowed dark neutrino mass range. Intriguingly,
their decays can also explain a neutrino flux excess at ${\cal O}(100\,{\rm
TeV})$ energies recently confirmed by the IceCube collaboration analysing 7.5yr
HESE data. Our results also point to an effective scale for Higgs portal
interactions nicely identifiable with the grandunified scale and many orders of
magnitude below the effective scale for the mixing. We explain this hierarchy
in a UV-complete model with a very heavy fermion as mediator: the first scale
corresponds to the fundamental scale of new physics, while the second is much
higher because of a very small coupling identifiable with a symmetry breaking
parameter. Therefore, RHINO realises a simple unified model of neutrino masses
and origin of matter in the universe currently under scrutiny at neutrino
telescopes and potentially embeddable within a grandunified model.
