Primordial Black Hole Evaporation and Dark Matter Production: II. Interplay with the Freeze-In/Out Mechanism

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We study how the evaporation of primordial black holes (PBHs) can affect the production of dark matter (DM) particles through thermal processes.

• We consider fermionic DM interacting with Standard Model particles via a spin-1 mediator in the context of a Freeze-Out or Freeze-In mechanism.
• We show that when PBHs evaporate after dominating the Universe's energy density, PBHs act as a source of DM and continuously inject entropy into the visible sector that can affect the thermal production in three qualitatively different ways.
• We compute the annihilation cross-sections which account for the interactions between and within the PBH produced and thermally produced DM populations, and establish a set of Boltzmann equations which we solve to obtain the correct relic abundance in those different regimes and confront the results with a set of different cosmological constraints.