Leptogenesis via Varying Weinberg Operator: a Semi-Classical Approach

TL;DR

This paper proposes a semi-classical mechanism for leptogenesis driven by a dynamically varying Weinberg operator, where a phase transition induces lepton asymmetry through interference effects near bubble walls.

Contribution

It introduces a novel semi-classical approach to leptogenesis involving a varying Weinberg operator triggered by symmetry breaking and phase transition dynamics.

Findings

Lepton asymmetry arises from interference of the Weinberg operator at different spacetime points.

Reflection asymmetry between leptons and anti-leptons is generated near bubble walls.

The approach successfully computes the final lepton asymmetry from quasiparticle equations of motion.

Abstract

In this Letter, we introduce leptogenesis via a varying Weinberg operator from a semi-classical perspective. This mechanism is motivated by the breaking of an underlying symmetry which triggers a phase transition that causes the coupling of the Weinberg operator to become dynamical. Consequently, a lepton anti-lepton asymmetry arises from the interference of the Weinberg operator at two different spacetime points. Using this semi-classical approach, we treat the Higgs as a background field and show a reflection asymmetry between the leptons and anti-leptons is generated in the vicinity of the bubble wall. We solve the equations of motion of the lepton and anti-lepton quasiparticles to obtain the final lepton asymmetry.