TY - GEN
AB - The lepton asymmetry of the universe is just weakly constraint and might
be orders of magnitude larger than the baryon asymmetry. In this thesis, we
investigate how a lepton asymmetry influences the cosmic trajectory through
the phase diagram of Quantum Chromodynamics (QCD). Therefore, we develop
a technique to determine the temperature evolution of chemical potentials
during the QCD epoch of the early universe at arbitrary lepton flavor
asymmetries. We will rely on an ideal quark gas approximation at high temperatures,
T > 150 MeV, and a hadron resonance gas model at low temperatures,
T < 250 MeV. Higher-order perturbative corrections are (partially)
included in the ideal quark gas approximation. To interpolate between these
approximations, we will for the first time use lattice QCD susceptibilities
to properly account for strong interaction effects close to the QCD transition
temperature TQCD. We therefore use a Taylor series ansatz of the QCD
pressure up to second order in the chemical potentials. With this technique
we investigate the impact of equally and unequally distributed lepton flavor
asymmetries on the cosmic trajectory. We conclude with an estimate on the
reliability of our technique via using a Taylor series of the QCD pressure.
AU - Wygas, Mandy
ID - 2934451
TI - Large Lepton Asymmetry and the Cosmic QCD Transition
ER -