Seesaw and leptogenesis: a triangular ansatz

TL;DR

This paper investigates a specific triangular ansatz for the seesaw mechanism and leptogenesis, simplifying the Dirac mass matrix to an upper triangular form to analyze lepton mixing and baryogenesis.

Contribution

It introduces a novel triangular ansatz for the Dirac mass matrix in the seesaw mechanism, focusing on the case where the unitary matrix is the identity.

Findings

Constraints from bilarge lepton mixing are analyzed.

Leptogenesis conditions are studied within this ansatz.

The triangular form simplifies the analysis of the seesaw and leptogenesis.

Abstract

A triangular ansatz for the seesaw mechanism and baryogenesis via leptogenesis is explored. In a basis where both the charged lepton and the Majorana mass matrix are diagonal, the Dirac mass matrix can generally be written as the product of a unitary times a triangular matrix. We assume the unitary matrix to be the identity and then an upper triangular Dirac matrix. Constraints from bilarge lepton mixing and leptogenesis are studied.