Family non-universal Z' models with protected flavor-changing interactions

TL;DR

This paper introduces a new class of Z' models with flavor-changing interactions and non-universal lepton couplings, which are highly predictive and can explain current anomalies in B-meson decays while making testable predictions for collider experiments.

Contribution

The paper proposes a novel class of Z' models with flavor-changing and lepton-flavor non-universal couplings, directly linked to the quark mixing matrix and gauge symmetry, providing a predictive framework.

Findings

Models can explain deviations in B-meson decay observables.

Predict lepton-universality violations in Z' decays at the LHC.

Establish correlations among Wilson coefficients in flavor transitions.

Abstract

We define a new class of $Z'$ models with neutral flavor-changing interactions at tree level in the down-quark sector. They are related in an exact way to elements of the quark mixing matrix due to an underlying flavored $U(1)'$ gauge symmetry, rendering these models particularly predictive. The same symmetry implies lepton-flavor non-universal couplings, fully determined by the gauge structure of the model. Our models allow to address presently observed deviations from the SM and specific correlations among the new physics contributions to the Wilson coefficients $C_{9,10}^{(\prime) \ell}$ can be tested in $b \to s \ell^+ \ell^-$ transitions. We furthermore predict lepton-universality violations in $Z'$ decays, testable at the LHC.