Multi-component dark matter: the vector and fermion case

Abstract

Multi-component dark matter scenarios constitute natural extensions of standard single-component setups and offer attractive new dynamics that could be adopted to solve various puzzles of dark matter. In this work we present and illustrate properties of a minimal UV-complete vector-fermion dark matter model where two or three dark sector particles are stable. The model we consider is an extension of the Standard Model (SM) by spontaneously broken extra U (1) X gauge symmetry and a Dirac fermion. All terms in the Lagrangian which are consistent with the assumed symmetry are present, so the model is renormalizable and consistent. To generate mass for the dark-vector X µ the Higgs mechanism with a complex singlet S is employed in the dark sector. Dark matter candidates are the massive vector boson X µ and two Majorana fermions ψ ± . All the dark sector fields are singlets under the SM gauge group. The set of three coupled Boltzmann equations has been solved numerically and discussed. We have performed scans over the parameter space of the model implementing the total relic abundance and direct detection constraints. The dynamics of the vector-fermion dark matter model is very rich and various interesting phenomena appear, in particular, when the standard annihilations of a given dark matter are suppressed then the semi-annihilations, conversions and decays within the dark sector are crucial for the evolution of relic abundance and its present value. Possibility of enhanced self-interaction has been also discussed.

Multi-component scalar dark matter from a ZN symmetry: a systematic analysis

“…not received as much attention but they are entirely compatible with current observations (see for instance [11][12][13][14][15][16]).…”

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.…”

Strong dark matter self-interaction from a stable scalar mediator

“…On the other hand, in the model with a scalar mediator, even though the DM indirect detection constraints can be avoided since the fermionic DM annihilation is p-wave dominated [54], the DM direct detection upper bounds [55] imply the longevity of the scalar mediator, which would modify the primordial abundances of light elements during Big-Bang nucleosynthesis (BBN) [56][57][58]. Though, there have already been many possible solutions proposed to avoid such tensions for models with scalar and vector mediators [54,[59][60][61][62][63][64][65][66][67][68][69].…”

“…In the present paper, inspired by Refs. [65,68,69], we construct and study a DM model in which the dominant DM component is a fermionic particle with a stable light scalar mediator. The stable mediator constitutes a subdominant DM by the freeze-out of its annihilation into additional light scalar particles.…”