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Free keywords:
High Energy Physics - Phenomenology, hep-ph,Astrophysics, Cosmology and Extragalactic Astrophysics, astro-ph.CO,High Energy Physics - Experiment, hep-ex
Abstract:
The scotogenic model proposed by Ernest Ma represents an attractive and
minimal example for the generation of small Standard Model neutrino masses via
radiative corrections in the dark matter sector. In this paper, we demonstrate
that, in addition to neutrino masses and dark matter, the scotogenic model also
allows to explain the baryon asymmetry of the Universe via low-scale
leptogenesis. First, we consider the case of two right-handed neutrinos (RHNs)
N_{1,2}, for which we provide an analytical argument why it is impossible to
push the RHN mass scale below M_1^min ~ 10^10 GeV, which is identical to the
value in standard thermal leptogenesis in the type-I seesaw scenario with the
same washout strength. Then, we present a detailed study of the three-RHN case
based on both an analytical and a numerical analysis. In the case of three
RHNs, we obtain a lower bound on the N_1 mass of around 10 TeV. Remarkably
enough, successful low-scale leptogenesis can be achieved without any
degeneracy in the RHN mass spectrum. The only necessary condition is a
suppression in the N_1 Yukawa couplings, which results in suppressed washout
and a small active neutrino mass of around 10^-12 eV. This leads to the
fascinating realization that low-scale leptogenesis in the scotogenic model can
be tested in experiments that aim at measuring the absolute neutrino mass
scale.
