Neutrino mass observables and non-Hermitian version of Type-I seesaw model

TL;DR

This paper explores a non-Hermitian extension of the Type-I seesaw model with singlet neutrinos, analyzing neutrino observables, mixing, and CP violation, and constrains model parameters using experimental data and leptogenesis considerations.

Contribution

It introduces a non-Hermitian framework for neutrino mass generation, applying four-zero textures to constrain parameters and studying implications for neutrino mixing and CP violation.

Findings

Non-Hermitian parameters are constrained by experimental neutrino data.

Mixing angles and CP phase are compatible with observations.

Leptogenesis imposes additional constraints on the model.

Abstract

We study the non-Hermitian extension of the Lagrangian of the Standard Model extended by singlet right-handed heavy neutrinos. The Yukawa coupling matrices comprise of hermitian and non-hermitian components and the neutrino mass eigenvalues are calculated for three generation case. The increased number of unknown parameters in the theory due to non-hermitian nature of coupling matrices impose problem for its productiveness. Hence we apply four zero texture for the Yukawa matrices. We consider the normal hierarchy of neutrino mass ordering and find the mixing angles and Dirac CP violating phase by diagonalizing the lepton mass matrices. The parameters of the mixing matrix are obtained in terms of the parameters of the non-hermitian Yukawa coupling matrix. The values of the angles and phase are compatible with experimental data available for neutrino mass observables and using this the non-hermitian parameters are constrained. Also, we study the constraints imposed by $CP$ violation in the lepton sector and leptogenesis on the model parameters.