Abstract
The exo-Higgs model can accommodate a successful baryogenesis mechanism that closely mirrors electroweak baryogenesis in the Standard Model, but avoids its shortcomings. We extend the exo-Higgs model by the addition of a singlet complex scalar $\chi$. In our model, $\chi$ can be a viable asymmetric dark matter (ADM) candidate. We predict the mass of the ADM particle to be $m_\chi\approx1.3\, \textrm{GeV}$. The leptophilic couplings of $\chi$ can provide for efficient annihilation of the ADM pairs. We also discuss the LHC signals of our scenario, and in particular the production and decays of exo-leptons which would lead to "lepton pair plus missing energy" final states. Our model typically predicts potentially detectable gravitational waves originating from the assumed strong first order phase transition at a temperature of $\sim$ TeV. If the model is further extended to include new heavy vector-like fermions, {\it e.g.} from an ultraviolet extension, $\chi$ couplings could explain the $\sim 3.5\sigma $ muon $g-2$ anomaly.
Highlights
In Ref. [1], we introduced the exo-Higgs η associated with breaking a new SU (2)e gauge interaction that we dubbed exo-spin [since the Standard Model (SM) particles do not carry SU (2)e charge and this force is outside the SM]
We presented a simple model addressing two major problems of cosmology, baryogenesis and the ratio of DM to baryonic matter energy densities, and predicting the mass of DM
Requiring that χ is lighter than all the other particles carrying Qχ, we ensure that χ is a stable particle and a good asymmetric DM candidate
Summary
In Ref. [1], we introduced the exo-Higgs η associated with breaking a new SU (2)e gauge interaction that we dubbed exo-spin [since the Standard Model (SM) particles do not carry SU (2)e charge and this force is outside the SM]. The addition of χ removes ad hoc mass scales that appeared in the original exo-Higgs model and replaces them with the Yukawa couplings of χ to charged exo-leptons and SM leptons. This scalar can be stable and provide a viable asymmetric dark mat-. It is still possible to explain the deviation in our framework, once we assume the existence of a new scale of physics above ∼ few TeV While this assumption could seem gratuitous, it is a well-motivated extension of our base model if, as detailed below, we assume that scalar mass parameters originate from higher scale symmetry breaking. We will briefly outline the main ingredients of the exo-Higgs model and minimal extensions of it mentioned above
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