The LHCb anomaly and $B$ physics in flavored Z$^{\prime}$ models with flavored Higgs doublets

P. Ko, Yuji Omura, Yoshihiro Shigekami, Chaehyun Yu

Published 2017-02-28Version 1

We study an extended Standard Model with a gauged U(1)$^\prime$ flavor symmetry, motivated by not only the fermion mass hierarchy but also the excesses in $B \to K^{(*)} l l$ reported by the LHCb collaborations. The U(1)$^\prime$ charges are assigned to quarks and leptons flavor-dependently and flavored Higgs doublets are also introduced to write down the Yukawa couplings at the renormalizable level. Then, the fermion mass hierarchy is realized by the vacuum alignment of the Higgs doublets. In this model, flavor changing currents involving the gauge boson of U(1)$^\prime$ and the scalars generated by the Higgs doublets are predicted and the observables in the $B \to K^{(*)} l l$ process are possibly deviated from the Standard-Model predictions. We study the possibility that the new flavor changing interactions explain the excesses in the process, and we derive some predictions for the other flavor violating processes based on the analysis. We especially investigate the $\Delta F=2$ processes and the other $B$ decays: e.g., $B \to X_s \gamma$ and $B \to D^{(*)} \tau \nu$, where the deviations are reported by the Belle and BaBar collaborations.