Filtered cogenesis of PBH dark matter and baryons

Abstract

We propose a novel cogenesis of baryon and dark matter (DM) in the Universe by utilising a first-order phase transition (FOPT) in the dark sector containing an asymmetric Dirac fermion $\chi$. Due to the mass difference of $\chi$ across the bubble walls, it is energetically favourable for $\chi$ to get trapped in the false vacuum leading to the formation of Fermi-ball, which can self-collapse to form primordial black hole (PBH) if $\chi$ has a sufficiently large Yukawa interaction. While such PBH formed out of false vacuum collapse can give rise to the DM in the Universe, a tiny amount of asymmetric $\chi$ leaking into the true vacuum through the bubble walls can transfer the dark asymmetry into the visible sector via decay. The same mass difference of $\chi$ across the two minima which decides the amount of trapping or filtering of $\chi$, also allows $\chi$ decay into visible sector in the true minima while keeping it stable in the false vacuum. Our filtered cogenesis scenario can be probed via FOPT generated stochastic gravitational waves (GW) at near future detectors in addition to the well-known detection aspects of asteroid mass PBH constituting DM in the Universe.