Towards Cogenesis via Asymmetric Freeze-in: The $\chi$ Who Came-in from the Cold

Understand

In models of freeze-in the dark matter (DM) is decoupled from the visible sector and initially has a depleted number density.

• The hidden and visible sectors are connected only via a feeble portal interaction by which DM can be produced.
• Asymmetric freeze-in (AFI) combines this scenario with ideas from asymmetric DM and provides a potential cogenesis mechanism.
• However, it has been argued that existing AFI models do not produce suitably large particle asymmetries due to cancellations which arises because the mediator state remains in thermal equilibrium.