Natural neutrino mass hierarchy in a theory of gauge flavour deconstruction

TL;DR

This paper demonstrates how a natural neutrino mass hierarchy with large lepton mixing angles can be achieved through gauge flavour deconstruction, challenging the notion of neutrino anarchy in such theories.

Contribution

It introduces a minimal tri-hypercharge model showing how family hypercharge decomposition and charged lepton hierarchy lead to neutrino mass hierarchy and mixing, with new sequential dominance results.

Findings

Neutrino mass hierarchy can arise naturally without anarchy.

Lepton mixing originates from both neutrino and charged lepton sectors.

The framework includes natural quark mass and mixing.

Abstract

We show how a natural neutrino mass hierarchy with large lepton mixing angles may be achieved in a theory of gauge flavour deconstruction. Hitherto it has been shown that neutrino anarchy may result from such theories, but here we show that this need not necessarily be the case. In particular we consider the minimal tri-hypercharge theory, and show that the decomposition of the family hypercharges into the corresponding $B-L$ gauge groups, together with the charged lepton mass hierarchy, implies the sequential dominance conditions for a neutrino mass hierarchy, where lepton mixing originates from both the neutrino and charged lepton sectors. We present novel and model-independent sequential dominance results applicable to this case, but also useful more generally. We also show how natural quark mass and mixing are included in such a framework.