Systematic analysis of leptogenesis in non-equilibrium QFT
Kartavtsev, Alexander (Max-Planck Institut for Nuclear Physics)

We apply the formalism of non-equilibrium QFT to study resonant leptogenesis and find that the canonical expression for the CP-violating parameter is only applicable in the hierarchical case. In the resonant regime medium corrections modify the canonical expression for the CP-violating parameter. Furthermore, the medium enhancement of the decay widths leads to a faster decay of the heavy neutrinos and an increased washout of the asymmetry. We also investigate the role of the two-body scattering processes and show that they do not contain contributions from the real intermediate states and are CP-violating.