Third Family Hypercharge Model for $R_{K^{(\ast )}}$ and Aspects of the Fermion Mass Problem

Abstract

We present a model to explain LHCb's 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.

22 pages. BRs in Table 2 corrected (error introduced in v5). v4 accepted for publication by JHEP

References in corpus (18)

• B-physics anomalies: a guide to combined explanations
• Explaining $h\to {\mu }^{\pm }{\tau }^{\mp }$, $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ and $B\to K{\mu }^{+}{\mu }^{-}/B\to K{e}^{+}{e}^{-}$ in a two-Higgs-doublet model with gauged $L_{\mu }-L_{\tau }$
• A three-site gauge model for flavor hierarchies and flavor anomalies
• Lepton Flavor Violation in B Decays?
• Baryon Number and Lepton Universality Violation in Leptoquark and Diquark Models
• Third Family Quark-Lepton Unification at the TeV Scale
• Phenomenology of an $SU(2)\times SU(2)\times U(1)$ model with lepton-flavour non-universality
• Z-Z' Mixing and Z-Mediated FCNCs in SU(3)_C x SU(3)_L x U(1)_X Models
• Penguin $b\to s{\ell }^{\prime +}{\ell }^{\prime -}$ and $B$-meson anomalies in a gauged $L_{\mu }-L_{\tau }$
• Neutrino mixing and $R_K$ anomaly in $U(1{)}_X$ models: a bottom-up approach
• LHCb anomalies from a natural perspective
• $B$-meson anomalies and Higgs physics in flavored $U(1{)}^{\prime }$ model
• $R_{K^{(\ast )}}$ and the origin of Yukawa couplings
• The Case for Future Hadron Colliders From $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$ Decays
• Connecting $b\to s\ell \bar{\ell }$ anomalies to enhanced rare nonleptonic ${\bar{B}}_s^0$ decays in $Z^{\prime }$ model
• Ansatz for small FCNC with a non-universal $Z^{\prime }$
• Recent $\mathbf{B}$ Physics Anomalies - a First Hint for Compositeness?
• Top Hypercharge

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