It is known that the radiative neutrino mass model proposed by Ma could be a
consistent framework for dark matter, leptogenesis and suppressed lepton flavor
violation if a neutral component of the inert doublet is identified as dark
matter and the right-handed neutrinos are of O(10^7) GeV or more. In the same
model we explore another scenario such that right-handed neutrinos are in TeV
regions and their lightest one is dark matter. It is shown that this scenario
requires fine mass degeneracy to generate the appropriate baryon number
asymmetry as in the case of resonant leptogenesis. As long as we impose the
model to induce the baryon number asymmetry on the basis of thermal
leptogenesis, we find that dark matter abundance can not be explained. If this
scenario is adopted, the model has to be extended to include some new mechanism
to explain it.Comment: 21 pages, 3 figures, v2:large improvement by the analysis of
Boltzmann equations, title changed, v3: abstract rewritten, some references
added, accepted version for publicatio
