We first suggested a scenario in which a generic, dark chiral gauge group undergoes a first order phase transition in order to generate the observed baryon asymmetry in the universe, provide a viable dark matter candidate and explain the observed baryon-to-dark matter ratio of relic abundances (1). We now provide a model in which a copy of the electroweak gauge group is added to the Standard Model. We spontaneously break this new gauge group to the diagonal Z2 center which is used to stabilize a dark matter candidate. In addition to the dark matter candidate, anomaly free messenger fermions are included which transform non-trivially under all the gauge groups. In analogy to electroweak baryogenesis, the model generates an excess of messenger baryons. These baryons subsequently decay to the Standard Model and dark matter to generate an excess of Standard Model baryons. The baryon-to-dark matter number density ratio is ultimately due to the requirement of gauge anomaly freedom. Dark sphalerons generate operators which violate baryon minus lepton (B - L) number but preserves baryon plus lepton number (B + L). This ensures any baryon asymmetry generated by the dark phase transition will not be washed out by the Standard Model.
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