Münster 2017 – scientific programme

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T: Fachverband Teilchenphysik

T 42: Astroteilchenphysik/Kosmologie (Theorie) 1

T 42.1: Talk

Tuesday, March 28, 2017, 11:00–11:15, VSH 17

Evolution of Chemical Potentials at Large Lepton Asymmetries — •Mandy M. Wygas and Dietrich Bödeker — Universität Bielefeld, Deutschland

An important phase in the early universe is the quark-hadron transition. It is well established that the order of the transition depends on the baryon density, or equivalently on the baryonchemical potential µ_B. In the QCD phase diagram in the µ_B−T plane, the cosmic QCD transition is commonly assumed to take place at vanishing baryonchemical potential µ_B≈ 0. However, as the baryon chemical potential also depends on lepton flavour asymmetries, this is only valid for a total lepton asymmetry l of the order of the baryon asymmetry, | l|≈O(b). While the magnitude of the baryon asymmetry, b≃ 10⁻¹⁰, can be determined by observations, l is only poorly constrained by observations and might be orders of magnitude larger than b, | l| 10⁻². Thus potentially large lepton flavour asymmetries induce a large µ_B.