B- c→η’ℓ-ν̄ decay and lepton polarization asymmetry

In this paper we study the lepton polarization asymmetry for the semileptonic OZI-forbidden annihilation decay B^- _c→η’ℓ^-ν̄, where ℓ=μ,τ. Our results show that the branching ratios turn out to be of order 10^-4. Besides, we find that longitudinal, transversal and normal components of lepton polarizations can be measured for both μ and τ decay modes in the future experiments at the LHC. PACS 14.40.Nd; 13.20.He; 13.60.-r; 11.30.Er