Disentangling Mass and Mixing Hierarchies

TL;DR

This paper introduces a perturbative mechanism that naturally creates fermion mass hierarchies in the Standard Model by enforcing alignment among flavor-breaking spurions, independent of flavor violation sources, with broad applications in beyond Standard Model theories.

Contribution

It proposes a novel perturbative approach to generate fermion mass hierarchies through alignment of flavor-breaking spurions, applicable at potentially low energy scales.

Findings

Mechanism enforces simultaneous diagonalization of flavor-breaking spurions.

Generates highly singular spectra for flavor-breaking spurions.

Applicable to model building beyond the Standard Model.

Abstract

We present a fully perturbative mechanism that naturally generates mass hierarchies for the Standard Model (SM) fermions in a flavor-blind sector. The dynamics generating the mass hierarchies can therefore be independent from the source of flavor violation, and hence this dynamics may operate at a much lower scale. This mechanism works by dynamically enforcing simultaneous diagonalization - alignment - among a set of flavor-breaking spurions, as well as generating highly singular spectra for them. It also has general applications in model building beyond the SM, wherever alignment between exotic and SM sources of flavor violation is desired.