B s → ϕl + l − decays in the topcolor-assisted technicolor model

Abstract

Using the updated form factors within the light-cone QCD sum rule approach, we calculate the new physics contributions to rare semileptonic $ \overline B {\text{s}} $ → ϕμ + μ − , ϕτ + τ − decays from the new particles appearing in the topcolor-assisted technicolor (TC2) model. In our evaluations, we find that: (i) the branching ratio, normalized forward-backward asymmetry and lepton polarization asymmetries show highly sensitivity to charged toppions contributions and little sensitivity to Z ′ contributions. The TC2 enhancements to the branching ratios of these decays can reach a factor of ~ 2; (ii) the NP enhancement to the forward-backward asymmetry of the decay B s → ϕμ + μ − is in the range −13 % to 3 %, but −9 % to −6 % for decay B s → ϕτ + τ − compared to the SM predictions; (iii) the TC2 model provide an enhancement of about 12 % to the longitudinal polarization asymmetry P L for decay B s → ϕμ + μ −, but a decrease of about 10 % to the transverse polarization asymmetry P T for the decay B s → ϕτ + τ −.