A new look at b → s observables in 331 models

Flavour changing neutral current (FCNC) processes are described by loop diagrams in the Standard Model (SM), while in 331 models, based on the gauge group SU(3)_C ×SU(3)_L ×U(1)_X, they are dominated by tree-level exchanges of a new heavy neutral gauge boson Z'. Exploiting this feature, observables related to FCNC decays of K, B_d and B_s mesons can be considered in several variants of 331 models. The variants are distinguished by the value of a parameter β that plays a key role in this framework. Imposing constraints on the Δ F = 2 observables, we select possible ranges for the mass of the Z' boson in correspondence to the values β = ± k / √(3), with k = 1, 2. The results are used to determine the impact of 331 models on b → s processes and on the correlations among them, in the light of new experimental data recently released.