Leptogenesis in an extended seesaw model with $U(1)_{B-L}$ symmetry

TL;DR

This paper proposes an extended seesaw model with $U(1)_{B-L}$ symmetry that naturally explains the Universe's matter-antimatter asymmetry through resonant leptogenesis, incorporating a keV sterile neutrino and avoiding fine-tuning.

Contribution

It introduces a novel extended seesaw framework with a keV sterile neutrino that enhances leptogenesis and aligns with neutrino and cosmological data without fine-tuning.

Findings

Resonant leptogenesis successfully explains baryon asymmetry.

Enhanced lepton asymmetry due to sterile neutrino effects.

Model remains consistent with neutrino mass and cosmology constraints.

Abstract

We have explored an extended seesaw model accommodating a keV sterile neutrino adopting $U(1)_{B-L}$ symmetry. This model provides a natural platform for achieving resonant leptogenesis to account for the observed baryon asymmetry of the Universe. The required lepton asymmetry is sourced by the CP violating decay of the lightest heavy right handed neutrino to Standard Model leptons and Higgs. The presence of the light sterile neutrino in the model brings out an enhancement in the final lepton asymmetry through an additional self-energy contribution. Adopting a proper treatment for all the washout processes this framework strictly favors a strong washout regime thereby protecting the low energy neutrino mass parameters in agreement with the present neutrino and cosmology data. This framework of extended seesaw scheme offers the source of matter-antimatter asymmetry without any severe fine tuning of the Yukawa couplings governing the tiny neutrino mass. We also comment on the half-life period for the neutrino less double beta decay process in the background of having a keV sterile neutrino satisfying all the constraints which guide the explanation for the observed baryon asymmetry of the Universe.