Micro-Bose/Proca dark matter stars from black hole superradiance

Abstract

We study the production of heavy, $\hat{I}¼\gtrsim 1$ TeV, bosonic spin $s=0,1$ dark matter (DM) via the simultaneous processes of Hawking evaporation and superradiance (SR) from an initial population of small, $\lesssim 10^6$ kg, primordial black holes (PBHs). Even for small initial PBH spins the SR process can produce extremely dense gravitationally-bound DM Bose or Proca soliton "stars" of radius $\lesssim \mathrm{pm}$ and mass $\sim 10^{\mathrm{few}}$ kg that can survive to today, well after PBH decay. These solitons can constitute a significant fraction of the DM density, rising to $\gtrsim 50\%$ in the vector DM case.

5 pages, 2 figures