LIGO/Virgo Black Holes from a First Order QCD Phase Transition

Abstract

We propose that $O(10 M_{\rm Sun})$ black holes observed by LIGO/Virgo originate from a first order QCD phase transition at a temperature $T_* \lesssim 100$~MeV. This is realized by keeping the quark masses small compared to confinement scale down to $T\sim T_*$, making QCD transition first order. We implement this scenario using a light scalar that could potentially be a good dark matter candidate.