http://arxiv.org/abs/1906.03577
We study the possibility of singlet fermion dark matter and successful leptogenesis in minimal scotogenic model which also provides a common origin of dark matter and light neutrino masses. In this scenario, where the standard model is extended by three gauge singlet fermions and one additional scalar doublet, all odd under an in-built $Z_2$ symmetry, the lightest singlet fermion which also happens to be the lightest $Z_2$ odd particle, can be either thermal or non-thermal dark matter candidate depending upon the strength of its couplings with standard model leptons and the $Z_2$ odd scalar doublet. In both the scenarios, the $Z_2$ odd scalar doublet plays a non-trivial role either by assisting coannihilation with thermal dark matter or by providing a source for non-thermal dark matter via decay. The heavier $Z_2$ odd singlet fermion produces a net lepton asymmetry through its out-of-equilibrium decay into standard model leptons and $Z_2$ odd scalar doublet. We show that the requirement of producing the observed baryon asymmetry pushes the scale of leptogenesis in case of normal ordering of light neutrino masses to several order of magnitudes above TeV scale. In case of inverted ordering however, it is possible to have successful $N_2$ leptogenesis at a scale of few tens of TeV. Correct dark matter abundance can be realised either by thermal freeze-out or by freeze-in mechanism in different parts of the parameter space that can have interesting prospects for ongoing experiments.
D. Mahanta and D. Borah
Tue, 11 Jun 19
3/60
Comments: 33 pages, 15 figures
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