Probe a family non-universal Z′Z′ boson effects in B¯s→ϕμ+μ− decay

Motivated by the recent measurement on B(B¯s→ϕμ+μ−) by CDF Collaboration, we study the effects of a family non-universal Z′Z′ boson on rare semileptonic B¯s→ϕμ+μ− decay. In our evaluations, we analyze the dependences of the dimuon invariant mass spectrum and normalized forward–backward asymmetry on Z′Z′ couplings and show that these observables are highly sensitive to new Z′Z′ contributions. Three limiting scenarios are presented in the detailed analyses. Numerically, within the allowed ranges of Z′Z′ couplings under the constraints from B¯s−Bs mixing, B→πKB→πK, B¯d→(Xs,K,K⁎)μ+μ− decays and so on, B(B¯s→ϕμ+μ−) and AFB(L)(B¯s→ϕμ+μ−) could be enhanced by about 96%96% and 17%17% (133%133%) respectively at most by Z′Z′ contributions. However, B(B¯s→ϕμ+μ−) is hardly to be reduced. Furthermore, the zero crossing in AFB(B¯s→ϕμ+μ−) spectrum at low dimuon mass always exists.