Cosmology meets functional QCD: First-order cosmic QCD transition induced by large lepton asymmetries

TL;DR

This paper explores how large lepton asymmetries in the early universe could induce a first-order QCD phase transition, using functional QCD methods to analyze cosmic trajectories during the QCD epoch.

Contribution

It introduces the first calculation demonstrating the possibility of a first-order cosmic QCD transition driven by large lepton asymmetries, incorporating advanced QCD thermodynamics.

Findings

Large lepton asymmetries can trigger a first-order QCD transition.

Specific lepton asymmetry values are identified for different scenarios.

Functional QCD methods are used to derive thermodynamic quantities.

Abstract

The lepton flavour asymmetries of the Universe are observationally almost unconstrained before the onset of neutrino oscillations. We calculate the cosmic trajectory during the cosmic QCD epoch in the presence of large lepton flavour asymmetries. By including QCD thermodynamic quantities derived from functional QCD methods in our calculation our work reveals for the first time the possibility of a first-order cosmic QCD transition. We specify the required values of the lepton flavour asymmetries for which a first-order transition occurs for a number of different benchmark scenarios.