Name: Clemens Kiessig
 Institution: MPI for physics
 Title: Fermionic Quasiparticles in Leptogenesis
 Key Words: Leptogenesis, Thermal field theory, Hard Thermal Loop, Plasmino, Dispersion Relation
 Abstract: We calculate the decay rate of a Yukawa fermion in a thermal bath
using finite temperature cutting rules and effective Green\'s functions according to the hard thermal loop resummation technique. We apply this result to the decay of a heavy Majorana neutrino and, at higher temperature, the corresponding decay of a Higgs boson in leptogenesis. Compared to the usual approach where thermal masses are inserted into the kinematics of final states, we find that deviations arise through two different leptonic dispersion relations. The decay rates differ from the usual approach by more than one order of magnitude in the temperature range which is interesting for the weak washout regime.