Mass-derivative relations for leptogenesis

TL;DR

This paper develops a diagrammatic approach to thermal mass effects in leptogenesis, linking Higgs thermal masses to infrared divergence cancellations in decay and scattering processes, enhancing theoretical understanding.

Contribution

It introduces a diagrammatic representation of thermal mass effects derived from $S$-matrix unitarity, applicable to classical and quantum Boltzmann equations in leptogenesis.

Findings

Established a connection between Higgs thermal mass and infrared divergence cancellations.

Derived a diagrammatic method from $S$-matrix unitarity for thermal mass effects.

Applied the approach to seesaw type-I leptogenesis processes.

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.