b → s transitions in family-dependent U(1)' models

We analyze flavor-changing-neutral-current (FCNC) effects in the b s transitions that are induced by family non-universal U(1)′ gauge symmetries. After systematically developing the necessary formalism, we present a correlated analysis for the ΔB = 1,2 processes. We adopt a model-independent approach in which we only require family-universal charges for the first and second generations and small fermion mixing angles. We analyze the constraints on the resulting parameter space from B_s-_s mixing and the time-dependent CP asymmetries of the penguin-dominated B _d (π,φ,η′,ρ,ω,f₀)K_S decays. Our results indicate that the currently observed discrepancies in some of these modes with respect to the Standard Model predictions can be consistently accommodated within this general class of models.