Neutrino mass and leptogenesis in a hybrid seesaw model with a spontaneously broken CP

TL;DR

This paper proposes a hybrid neutrino mass model combining type I and II seesaw mechanisms with spontaneous CP violation, explaining neutrino oscillations and baryon asymmetry via a detailed leptogenesis analysis.

Contribution

It introduces a novel hybrid framework with spontaneous CP violation that simultaneously addresses neutrino masses and baryon asymmetry.

Findings

Model explains neutrino oscillation data.

Leptogenesis driven by nearly degenerate scalar triplet and singlet neutrino fields.

Quantitative analysis supports viability of the scenario.

Abstract

We introduce a novel hybrid framework combining type I and type II seesaw models for neutrino mass where a complex vacuum expectation value of a singlet scalar field breaks CP spontaneously. Using pragmatic organizing symmetries we demonstrate that such a model can simultaneously explain the neutrino oscillation data and generate observed baryon asymmetry through leptogenesis. Interestingly, natural choice of parameters leads to a mixed leptogenesis scenario driven by nearly degenerate scalar triplet and right handed singlet neutrino fields for which we present a detailed quantitative analysis.