Exotic particles below the TeV from low scale flavour theories

TL;DR

This paper explores low-scale flavour gauge theories, proposing that observable flavour symmetry breaking occurs near the TeV scale, necessitating new fermions and addressing flavor violation suppression.

Contribution

It introduces benchmark supersymmetric flavour models showing that flavour symmetry breaking should be around three orders of magnitude above the higgsino mass, requiring new fermions with exotic decays.

Findings

Flavour symmetry breaking occurs near the TeV scale.

New fermions with exotic decays are predicted at higgsino-scale energies.

Suppression of FCNC and CP violations is achievable with this scale separation.

Abstract

A flavour gauge theory is observable only if the symmetry is broken at relatively low energies. The intrinsic parity-violation of the fermion representations in a flavour theory describing quark, lepton and higgsino masses and mixings generically requires anomaly cancellation by new fermions. Benchmark supersymmetric flavour models are built and studied to argue that: i) the flavour symmetry breaking should be about three orders of magnitude above the higgsino mass, enough also to efficiently suppress FCNC and CP violations coming from higher-dimensional operators; ii) new fermions with exotic decays into lighter particles are typically required at scales of the order of the higgsino mass.