# Leptonic Invariants, Neutrino Mass-Ordering and the Octant of $\theta_{23}$

## TL;DR

This paper demonstrates that leptonic weak-basis invariants are powerful tools for determining neutrino mass hierarchy and the octant of b8_{23} in lepton flavour models, providing basis-independent insights.

## Contribution

The authors show how to use leptonic weak-basis invariants to identify neutrino mass ordering and the b8_{23} octant, offering a basis-independent method for model analysis.

## Key findings

- Invariants can distinguish normal and inverted neutrino mass hierarchies.
- Invariants can determine the octant of b8_{23}.
- Invariants relate to neutrino and charged lepton masses, mixing angles, and CP phases.

## Abstract

We point out that leptonic weak-basis invariants are an important tool for the study of the properties of lepton flavour models. In particular, we show that appropriately chosen invariants can give a clear indication of whether a particular lepton flavour model favours normal or inverted hierarchy for neutrino masses and what is the octant of $\theta_{23}$. These invariants can be evaluated in any conveniently chosen weak-basis and can also be expressed in terms of neutrino masses, charged lepton masses, mixing angles and CP violation phases.