Lepton Flavor Non-Universality in B decays from Dynamical Yukawas

TL;DR

This paper proposes a dynamical Yukawa framework with gauged flavor symmetries that can naturally account for observed fermion mass patterns and explain anomalies in B decays through flavor gauge bosons, predicting observable signals at the LHC.

Contribution

It introduces a model with gauged flavor symmetries and dynamical Yukawas that explains fermion masses and flavor anomalies simultaneously, linking them to new gauge bosons at the TeV scale.

Findings

Flavor gauge bosons can explain B decay anomalies like R_K.

Model predicts observable dimuon resonance signals at the LHC.

Spontaneous symmetry breaking occurs around the TeV scale.

Abstract

The basic features of quark and lepton mass matrices can be successfully explained by natural minima of a generic potential with dynamical Yukawa fields invariant under the $[\mathrm{SU(3)}]^5\times \mathcal{O}(3)$ flavor symmetry. If this symmetry is gauged, in order to avoid potentially dangerous Goldstone bosons, and small perturbations are added to exactly fit the observed pattern of fermion masses, the spectrum of massive flavor gauge bosons can naturally explain the hints for new physics in $b\to s \ell^+\ell^-$ transitions, including $R_K$. In particular, the desired pattern of the Standard Model Yukawa couplings is compatible with a gauged $\mathrm{U(1)}_q$ in the quark sector, and $\mathrm{U(1)}_{\mu-\tau}$ in the lepton sector spontaneously broken around the TeV scale. In order to explain the aforementioned experimental hints, the corresponding neutral gauge bosons are required to mix, yielding to potentially observable signals in dimuon resonance searches at the LHC.