Heavy Baryon Dark Matter from $SU(N)$ Confinement: Bubble Wall Velocity and Boundary Effects

Abstract

Confinement in $SU(N_{\rm DC})$ Yang-Mills theories is known to proceed through first-order phase transition. The wall velocity is bounded by $v_w \lesssim 10^{-6}$ due to the needed time for the substantial latent heat released during the phase transition to dissipate through Hubble expansion. Quarks much heavier than the confinement scale can be introduced without changing the confinement dynamics. After they freeze-out, heavy quarks are squeezed into pockets of the deconfined phase until they completely annihilate with anti-quarks. We calculate the dark baryon abundance surviving annihilation, due to bound-state formation occurring both in the bulk and - for the first time - at the boundary. We find that dark baryons can be dark matter with a mass up to $10^3~\rm TeV$. We study indirect and direct detection, CMB and BBN probes, assuming portals to Higgs and neutrinos.