Rare semileptonic b → dµ < sup > + < /sup > µ < sup > − < /sup > transitions and effects of z < sup > ′ < /sup > in the 331 model

Abstract

We study the rare semileptonic B → ρμ+μ− decay mediated by b → dμ+μ− transition. Differential branching ratio, longitudinal lepton polarization and forward-backward asymmetry of B → ρμ+μ− are analyzed within the Standard Model in the low q2 region. We study the effects of Z′ in the 331 or SUC (3) × SUL (3) × UX (1) model on this decay mode by varying the model parameter β at MZ ′ = 1, 3 TeV. The couplings of Z′ are constrained by flavor observables of Bd − ¯Bd mixing. We find that the observables of interest are sensitive to Z′ effects and we observe deviations from the SM for some values of β.