Signatures of a High Temperature QCD Transition in the Early Universe

Understand

Beyond Standard Model extensions of QCD could result in quark and gluon confinement occurring well above a temperature of $\sim$GeV.

• These models can also alter the order of the QCD phase transition.
• The enhanced production of primordial black holes (PBHs) that can accompany the change in relativistic degrees of freedom at the QCD transition therefore could favor the production of PBHs with mass scales smaller than the Standard Model QCD horizon scale.
• Consequently, and unlike PBHs associated with a standard GeV-scale QCD transition, such PBHs can account for all the dark matter abundance in the unconstrained asteroid-mass window.