Neutrino Mixing from Wilson Lines in Warped Space

TL;DR

This paper explores how Wilson lines in warped extra dimensions can generate realistic neutrino masses and mixing angles, providing a framework consistent with experimental data and free of fine-tuning or flavor violation.

Contribution

It classifies all realistic neutrino mass generation scenarios in warped space models using Wilson lines, especially for Majorana neutrinos with bulk symmetries.

Findings

Achieves realistic neutrino spectra without fine-tuning.

No tree-level lepton flavor violation occurs.

Compatible with experimental constraints at TeV-scale KK modes.

Abstract

We consider the generation of the hierarchical charged lepton spectrum and anarchic neutrino masses and mixing angles in warped extra dimensional models with Randall-Sundrum metric. We have classified all possible cases giving rise to realistic spectra for both Dirac and Majorana neutrinos. An anarchic neutrino spectrum requires a convenient bulk symmetry broken by boundary conditions on both UV and IR branes. We have in particular considered the case of Majorana neutrinos with a continuous bulk symmetry. To avoid unwanted massless extra gauge bosons the 4D group should be empty. If the 4D coset is not vanishing it can provide a Wilson Line description of the neutrino Majorana mass matrix. We have studied an example based on the bulk gauge group U(3)_{L} \otimes U(3)_{N} \otimes_{i} U(1)_{E^i} with the Wilson Line in SO(3)_{N} satisfying all required conditions. A \chi^2-fit to experimental data exhibits the 95% CL region in the parameter space with no fine-tuning. As a consequence of the symmetries of the theory there is no tree-level induced lepton flavor violation and so one-loop processes are consistent with experimental data for KK-modes about a few TeV. The model is easily generalizable to models with IR deformed metrics with similar conclusions.