Lepton Polarization Asymmetry in B * s,d → μ + μ − with new Z ′ Couplings

We study the effect of non-universal Z ′ boson on the rare leponic decay modes of B_s^∗ mesons, mediated by b → sll quark transition. Rare B decays are sensitive to various new physics operators. As B mesons are composite particles, such decay modes of the excited states are ideal for probing new physics beyond the standard model. We have constrained our model parameters from B_s,d-B_s,d mixing data to predict the lepton polarization asymmetry of B_s,d^∗→μ^+μ^- channel. It is found that this asymmetry deviates from its SM prediction along with the Z ′ effect.