A Common Origin for Neutrino Anarchy and Charged Hierarchies

TL;DR

This paper explores how extra-dimensional wavefunction overlaps can naturally produce both fermion mass hierarchies and neutrino anarchy within a unified framework, with implications for flavor physics and supersymmetry.

Contribution

It demonstrates that fermion mass hierarchies and neutrino anarchy can coexist naturally in extra-dimensional models, and analyzes their phenomenological consequences including neutrino types and supersymmetric flavor issues.

Findings

Anarchic neutrino masses can coexist with charged fermion hierarchies.

Dirac neutrinos are favored over Majorana in certain supersymmetric scenarios.

Light right-handed sneutrinos impact dark matter physics.

Abstract

The generation of exponential flavor hierarchies from extra-dimensional wavefunction overlaps is re-examined. We find, surprisingly, that coexistence of anarchic fermion mass matrices with such hierarchies is intrinsic and natural to this setting. The salient features of charged fermion and neutrino masses and mixings can thereby be captured within a single framework. Both Dirac and Majorana neutrinos can be realized. The minimal phenomenological consequences are discussed, including the need for a fundamental scale far above the weak scale to adequately suppress flavor-changing neutral currents. Two broad scenarios for stabilizing this electroweak hierarchy are studied, warped compactification and supersymmetry. In warped compactifications and "Flavorful Supersymmetry," where non-trivial flavor structure appears in the new TeV physics, Dirac neutrinos are strongly favored over Majorana by lepton flavor violation tests. We argue that this is part of a more general result for flavor-sensitive TeV-scale physics. Our scenario strongly suggests that the supersymmetric flavor problem is not solved locally in the extra dimension, but rather at or below the compactification scale. In the supersymmetric Dirac case, we discuss how the appearance of light right-handed sneutrinos considerably alters the physics of dark matter.