Non-zero \theta_13 in models for hierarchical neutrino mass spectrum

TL;DR

This paper proposes a model combining type-I seesaw and inert doublet mechanisms with three right-handed neutrinos, explaining the hierarchical neutrino masses and predicting a correlation between the smallest mixing angle and the lightest neutrino mass.

Contribution

It introduces a novel framework combining two mechanisms and analyzes both hierarchy cases, revealing a new correlation in neutrino mixing parameters.

Findings

Correlation between _13 and lightest neutrino mass

Applicable to both inverted and normal hierarchies

Provides insights into neutrino mass scale and mixing

Abstract

We introduce three right-handed Majorana neutrinos and combine the type-I seesaw and inert doublet mechanisms. The resultant (active) neutrino mass matrix is divided into rank=1 and =2 parts with different energy scales. The different energy scales are reduce to different mass scales in the hierarchical neutrino mass spectrum. We apply this scheme to both the inverted and normal hierarchy cases and find a correlation between the smallest mixing angle (\theta_13) and the lightest neutrino mass.