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We present a model to explain LHCbs recent measurements of $R_K$ and $R_{K^{ast}}$ based on an anomaly-free, spontaneously-broken $U(1)_F$ gauge symmetry, without any fermionic fields beyond those of the Standard Model (SM). The model explains the hierarchical heaviness of the third family and the smallness of quark mixing. The $U(1)_F$ charges of the third family of SM fields and the Higgs doublet are set equal to their respective hypercharges. A heavy $Z^prime$ particle with flavour-dependent couplings can modify the $[overline{b_L} gamma^rho s_L][overline{mu_L} gamma_rho mu_L]$ effective vertex in the desired way. The $Z^prime$ contribution to $B_s-overline{B_s}$ mixing is suppressed by a small mixing angle connected to $V_{ts}$, making the constraint coming from its measurement easier to satisfy. The model can explain $R_K$ and $R_{K^{(ast)}}$ whilst simultaneously passing other constraints, including measurements of the lepton flavour universality of $Z$ couplings.
We further investigate the case where new physics in the form of a massive $Z^prime$ particle explains apparent measurements of lepton flavour non-universality in $B rightarrow K^{(ast)} l^+ l^-$ decays. Hadron collider sensitivities for direct produ
While it is known that third family hypercharge models can explain the neutral current $B-$anomalies, it was hitherto unclear whether the $Z-Z^prime$ mixing predicted by such models could simultaneously fit electroweak precision observables. Here, we
We identify a single six-dimensional effective operator $O_{ellell}$ that can account for the Cabibbo angle anomaly naturally, without any tension with the electroweak precision observables. The renormalization group running of $O_{ell ell}$ yields t
Precision measurements of the Higgs couplings are, for the first time, directly probing the mechanism of fermion mass generation. The purpose of this work is to determine to what extent these measurements can distinguish between the tree-level mechan
LHCb has reported hints of lepton-flavor universality violation in the rare decays $B to K^{(*)} ell^+ell^-$, both in high- and low-$q^2$ bins. Although the high-$q^2$ hint may be explained by new short-ranged interactions, the low-$q^2$ one cannot.