Predicting theta_13 and the Neutrino Mass Scale from Quark Lepton Mass Hierarchies

TL;DR

This paper uses Froggatt-Nielsen flavor symmetries and observed neutrino data to predict the smallest neutrino mixing angle, mass, and a Majorana phase with notable accuracy, revealing deep connections between quark-lepton hierarchies.

Contribution

It introduces a method to predict neutrino parameters by combining flavor symmetries with experimental data, constraining unknown parameters effectively.

Findings

Predicted sin^2(2 theta_13) = 0.07 (+0.11)(-0.05)

Estimated smallest neutrino mass m_1 = 2.2 (+1.7)(-1.4) x 10^-3 eV

Determined Majorana phase alpha_21 / pi = 1.0 (+0.2)(-0.2)

Abstract

Flavour symmetries of Froggatt-Nielsen type can naturally reconcile the large quark and charged lepton mass hierarchies and the small quark mixing angles with the observed small neutrino mass hierarchies and their large mixing angles. We point out that such a flavour structure, together with the measured neutrino mass squared differences and mixing angles, strongly constrains yet undetermined parameters of the neutrino sector. Treating unknown O(1) parameters as random variables, we obtain surprisingly accurate predictions for the smallest mixing angle, sin^2(2 theta_13) = 0.07 (+0.11)(-0.05), the smallest neutrino mass, m_1 = 2.2 (+1.7)(-1.4) x 10^-3 eV, and one Majorana phase, alpha_21 / pi = 1.0 (+0.2)(-0.2).