Investigating the 331-Z′ mediated FCNC effects on b → sμ < sup > + < /sup > μ < inf > - < /inf > transitions

Abstract

The rare semileptonic B → Kμ+μ- and B → Φμ+μ- decay modes mediated by the b → sμ+μ- transition are studied in this paper. We analyze observables such as the differential branching ratio, lepton polarization asymmetry and forward-backward asymmetry within the standard model in the low q2 region. We then perform an analysis of the same modes within the 331 or SUC(3) × SUL(3) × UX(1) model in which a new heavy Z′ boson contributes. The effects of the Z′-mediated flavor-changing neutral current (FCNC) transitions on these modes are investigated by varying the mass MZ′ and the model parameter β. The new Z′ couplings are constrained by flavor observables of Bs - Bs mixing and branching ratio of Bs → μ+μ-. We find that for some values of these couplings, the observables are quite sensitive to Z′ effects and deviations from Standard Model can be large.