Particle asymmetries in the early universe

摘要

The total lepton asymmetry l=∑_f~(lf) in our universe is only poorly constrained by theories and experiments. It might be orders of magnitudes larger than the observed baryon asymmetry b?O(10~(-10)), |l|b≤O(10~9). We found that the dynamics of the cosmic QCD transition changes for large asymmetries. Predictions for asymmetries in a single flavour ~(lf) allow even larger values. We find that asymmetries of ~(lf)≤O(1) in single or two flavours may change the relic abundance of WIMPs. However, large lepton and large individual lepton flavour asymmetries influence significantly the dynamics of the early universe between the electroweak phase transition and the onset of neutrino oscillations.