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

## TL;DR

This paper suggests that black holes observed by LIGO/Virgo could originate from a first order QCD phase transition in the early universe, involving a light scalar that might also be dark matter.

## Contribution

It introduces a novel scenario where a light scalar induces a first order QCD transition, explaining the origin of certain black holes and linking to dark matter.

## Key findings

- Black holes of around 10 solar masses can form from a first order QCD transition.
- A light scalar field can make the QCD transition first order at low temperatures.
- The scenario connects black hole formation with dark matter candidates.

## 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.