Primordial Black Holes from Conformal Higgs

Understand

Scale-invariant extensions of the electroweak theory are not only attractive because they can dynamically generate the weak scale, but also due to their role in facilitating supercooled first-order phase transitions.

• We study the minimal scale-invariant $U(1)_{\rm D}$ extension of the standard model and show that Primordial Black Holes (PBHs) can be abundantly produced.
• The mass of these PBHs is bounded from above by that of the moon due to QCD catalysis limiting the amount of supercooling.
• Lunar-mass PBHs, which are produced for dark Higgs vev $v_\phi\simeq 20~\rm TeV$, correspond to the best likelihood to explain the HSC lensing anomaly.