Mass-derivative relations for leptogenesis

Abstract

In this work, a diagrammatic representation of thermal mass effects is derived from the $S$-matrix unitarity both in the classical and quantum Boltzmann equations. Within the example of the seesaw type-I leptogenesis, we discuss the connection of the Higgs thermal mass and the cancelations of infrared divergences in zero- and finite-temperature calculations of the right-handed neutrino decay and scattering processes.