Two dark matter candidates: the case of inert doublet and singlet scalars

Abstract

We consider a multi-component dark matter model where the dark sector contains a scalar doublet and a complex scalar singlet. We impose a discrete Z 4 symmetry to ensure such that the lightest component of the doublet, Ã, and the singlet, S, are both stable. Interactions between the dark sectors impact significantly dark matter observables, they allow in particular to significantly relax the direct detection constraints on the model. To determine the parameter space that satisfies relic density, theoretical and collider constraints as well as direct and indirect detection limits, we perform two separate scans, the first includes the full parameter space of the model while the second is dedicated to scenarios with a compressed inert doublet spectrum. In the first case we find that the singlet is generally the dominant dark matter component while in the compressed case the doublet is more likely to be the dominant dark matter component. In both cases we find that the two dark matter particles can have masses that ranges from around m h /2 to over the TeV scale. We emphasize the interplay between cosmological astrophysical and collider constraints and show that a large fraction of the parameter space that escapes current constraints is within the sensitivity reach of future detectors such as XENON-nT, Darwin or CTA. Important collider signatures are mostly found in the compressed spectrum case with the possibility of probing the model with searches for heavy stable charged particles and disappearing tracks. We also show that semi-annihilation processes such as S S → ÃZ could give the dominant signature in indirect detection searches.

WIMP and FIMP dark matter in the inert doublet plus singlet model

“…In this case the dominant decay mode is H± → π ± Ã and the decay width is much larger than the one computed for decay into quarks H+ → u dA. More details of the implementation can be found in [28,31,32].…”

“…In a previous publication [28] we have examined carefully a model with two dark sectors, the inert doublet and singlet model (IDSM) which contains both a doublet and a singlet of scalars in addition to the standard model (SM) particles. The model also features a discrete Z 4 symmetry where the singlet and doublet have different charges [27,29].…”

“…This guarantees the stability of the singlet and of the lightest neutral component of the doublet if its decay to two singlets is kinematically forbidden. Within this framework we have shown how current constraints that affect both the inert doublet and singlet models that form subsets of the IDSM can be significantly relaxed notably because of the interactions between the two sectors [28]. In this publication we consider the same model but assume that the singlet is feebly interacting with the standard model such that it is not in thermal equilibrium in the early universe.…”

Constraining new physics with SModelS version 2

“…All in all, we sample 29k points that fulfill the above constraints in the region of small mass splittings, m H ± −m H 0 < 0.5 GeV, that gives long-lived charged scalars. The dominant decay modes of the 11 Following [31,56] (see also [57]), we add an effective…”

A Two-Component Dark Matter Model and its Associated Gravitational Waves

“…Recent studies on multi-component DM scenarios include Refs. [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60].…”