Speaker
Description
In this talk I discuss the constraints imposed by BBN and CMB observations on primordial lepton flavour asymmetries with (approximately) vanishing total lepton number. I show that solving the momentum averaged quantum kinetic equations describing neutrino oscillations and interactions is an accurate approximation to the full momentum-dependent system, and the results reveal a rich flavour structure in stark contradiction to the assumption of simple flavour equilibration. I will discuss the implications of the resulting BBN and CMB constraints on models of first-order QCD phase transition facilitated by large lepton asymmetries as well as leptogenesis from large and compensated flavour asymmetries. I will also present the publicly available COFLASY code (in both Mathematica and C++ versions) which evolves lepton flavour asymmetries from the early Universe to BBN times, being orders of magnitude faster than similar codes which solve the full-momentum dependent system.
