The Impact of Dark Matter on the Related Sector of the Scotogenic Model and Its Implications

Abstract

We investigate the impact of the recent results concerning the fit to the global data on neutrino oscillations,
the direct detection experiments of the dark matter, and the Planck measurement for the relic density on
the parameter space relevant to the fermionic dark matter sector of the scotogenic model. In this sector,
the lightest new singlet fermion is adopted to be the dark matter candidate. We show that masses of dark
matter and new scalars smaller than or equal to 1 TeV satisfying the strongest constraints arise from |Δm2
31|
Δm2
21
,
μ → eγ, and direct detection constraints do not guarantee that Ωˆh2 lies in the 2σ range provided recently
by the Planck satellite measurements with Δm2i
j = m2i
−m2j
. This result is valid for the case that the lightest
new singlet fermion N1 is the dark matter candidate and for the scenarios of normal and inverted ordering
of neutrino masses. Moreover, we find that if N1 is degenerate or nearly degenerate in mass with the next
lightest singlet fermion N2, the new contributions from coannihilation of N1 and N2 become relevant to
reduce the values of the Yukawa coupling needed for producing the relic density of dark matter within 2σ
range of its measured value while respecting the imposed constraints.