Particle asymmetries in the early universe

Abstract

The total lepton asymmetry $l={\sum }_f{l}_f$ in our universe is only poorly constrained by theories and experiments. It might be orders of magnitudes larger than the observed baryon asymmetry $b\simeq \mathcal{O}(10^{-10})$, $|l|/b\le \mathcal{O}(10^9)$. We found that the dynamics of the cosmic QCD transition changes for large asymmetries. Predictions for asymmetries in a single flavour $l_f$ allow even larger values. We find that asymmetries of $l_f\le \mathcal{O}(1)$ in a single or two flavours change the relic abundance of WIMPs. However, large lepton and large individual lepton flavour asymmetries influences significantly the dynamics of the early universe.

Comments: 7 pages,8 figures; Proceedings of the Erice workshop on Nuclear Physics 2010 "Particle and Nuclear Astrophysics"