Scale-invariant two-component dark matter

Abstract

We study a scale-invariant extension of the standard model which can simultaneously explain dark matter and the hierarchy problem. In our set-up, we introduce a scalar and a spinor as two-component dark matter in addition to a scalon field as a mediator. An interesting point about our model is that due to scale-invariant conditions, compared to other two-component dark matter models, it has fewer independent parameters. Possible astrophysical and laboratory signatures of a two-component dark matter candidate are explored and it is shown that the highest contribution of observed relic density of dark matter can be determined by spinor dark matter. The detectability of these dark matter particles is studied and direct and invisible Higgs decay experiments are used to rule out part of the parameter space of the model. In addition, the dark matter self-interactions are considered and it is shown that their contributions saturate this constraint in the resonant regions.