Discrete D3 dark matter

We consider the minimal model of dark matter stabilized by a non-abelian discrete symmetry. The symmetry group is taken to be D3 (or S3), which is the smallest non-abelian finite group. The minimal model contains (nontrivial) singlet and doublet scalar representations of D3 which couple to the Standard Model fields via the Higgs portal. This construction predicts multi-component dark matter over much of the parameter space. Non-trival interactions under D3 may affect the thermal history of the dark matter candidates, while the dual nature of dark matter can potentially be unraveled by direct detection experiments. Finally, the Higgs boson may decay invisibly if the dark matter states are light.