Phenomenology of a gauged SU(3) ³ avour model

We present an extensive analysis of ΔF = 2 observables and of B → X _sγ in the framework of a specific Maximally Gauged Flavour (MGF) model of Grinstein et al. including all relevant contributions, in particular tree-level heavy gauge boson exchanges whose effects are studied in detail in the present paper for the first time. The model allows in principle for significant deviations from the Standard Model predictions for ε _K, ΔM _Bd,s, mixing induced CP-asymmetries S _ψKS and S _ψφ and B → X _sγ decay. The tension between ε _K and S _ψKS present in the SM can be removed by enhancing εK without modifying S _ψKS. In this case, we find that in this model i) the results for S _ψφ and B → X _sγ turn out to be SM-like, ii) the exclusive determination of V _ub is favoured and most importantly iii) the values of ΔM _Bd and Δ _MBs being strongly correlated in this model with ε _K turn out to be much larger than the data for the central values of input parameters: ΔM _Bd ≈ 0:75=ps and ΔM _Bs ≈ 27=ps. Therefore, from the present perspective, the model suffers from a serious ε _K-ΔM _Bd,s tension. However, this tension can be softened considering theoretical and parametric uncertainties and in particular the decrease of the weak decay constants. On the other side, the model can be strongly constrained considering the theoretically cleaner ratios ΔM _Bd=ΔM _Bs and BR(B+ → τ ⁺V)= ΔM _Bd and we find that it is unable to remove simultaneously all the SM tensions on the data. Finally, we compare the pattern of avour violation in MGF with selected extensions of the SM.