Pasquale Dario Serpico (LAPTh Annecy)

QCD phase transition behind a primordial black hole origin of LIGO/Virgo events?

Motivated by the intriguing mass function in the LIGO/Virgo black hole events, I review the motivation to consider a primordial black hole (PBH) component as responsible for the heavy mass mergers. The QCD epoch in the early universe has been advocated as a ‘natural’ shaper of such a PBH mass function. We test this “QCD hypothesis” with a number of predictions (Super-massive Black Holes,  Cosmic Microwave Background anistropies, Gravitational Wave  events) and conclude that this neat mechanism cannot be the main responsible for the observations.