Multicomponent Dark Matter in Radiative Seesaw Models

Abstract

We discuss radiative seesaw models, in which an exact Z 2 × Z ′ 2 symmetry is imposed. Due to the exact Z 2 × Z ′ 2 symmetry, neutrino masses are generated at a two-loop level and at least two extra stable electrically neutral particles are predicted. We consider two models: one has a multi-component dark matter system and the other one has a dark radiation in addition to a dark matter. In the multi-component dark matter system, non-standard dark matter annihilation processes exist. We find that they play important roles in determining the relic abundance and also responsible for the monochromatic neutrino lines resulting from the dark matter annihilation process. In the model with the dark radiation, the structure of the Yukawa coupling is considerably constrained and gives an interesting relationship among cosmology, lepton flavor violating decay of the charged leptons and the decay of the inert Higgs bosons.

Two component dark matter with inert Higgs doublet: neutrino mass, high scale validity and collider searches

“…Non observation of DM in direct search experiments like LUX [25], XENON 1T [25][26][27], Panda X [28] put a stringent bound on this model (with mass below 1 TeV getting disallowed) due to its prediction of large spin independent (SI) direct search cross section. As an alternative, multi-component DM scenarios [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] are proposed where DM-DM interactions (see for example, [39,40]) play an important role to evade direct search bound.Such an attempt was made in [39], where two singlet scalars serve as two DM components, that satisfy required DM constraints. However, the framework is unable to accommodate the low mass region corresponding to both the DM's masses, simultaneously below 500 GeV, to satisfy DM direct search bounds.…”

Natural axion model from flavour

“…Hence the only requirement for the axion in our model being cold DM is to have a mass m DM a ≤ 10 −2 eV in order to fall in the range of any of the allowed scenarios. However, note that having multi-component DM is also a viable possibility [64][65][66][67][68][69][70][71][72][73][74] and the axion could be responsible for only a fraction of the DM density, thus relaxing the constraints. For more details on axion DM we refer the reader to [63].…”

Multipartite dark matter with scalars, fermions and signatures at LHC

“…Multipartite DM frameworks [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] can provide a cushion to the tension of WIMP like particles to satisfy simultaneously relic density and direct search constraints. This is essentially due to some processes which can still contribute to the depletion of DM number density for thermal freeze-out, but do not contribute to direct search cross-sections.…”