Speaker
Description
Primordial black holes (PBHs) may have formed in the early Universe, and yet constitute only a sub-dominant component of the dark matter. In that case, the rest of the dark matter is expected to build up mini-halos with steep density profiles (“spikes”) around the PBHs. If this second dark matter component is in the form of Weakly Interacting Massive Particles (WIMPs), their annihilation rate would be enhanced by the high density environment of the spikes, a scenario that was shown to lead to extremely strong constraints on WIMPs. In this work, we revisit constraints that can be set on this mixed WIMP+PBH scenario from the observation of the cosmic microwave background. In particular, we improve on proevious calculations in the literature thanks to a careful computation of the dark matter spike profile as a function of black hole mass, dark matter particle mass and temperature of kinetic decoupling.
