Exclusive B→Mℓ+ℓ−(M=π, K, ρ, K∗) decays and determinations of Vts (and Vtd/Vts)

We examine the possibility for precise determination of Vts (and Vtd/Vts) from the exclusive decays, B→Kℓ+ℓ−, B→K∗ℓ+ℓ− (and B→πℓ+ℓ−, B→ρℓ+ℓ−). We show that the ratio Vts can be extracted experimentally with a small theoretical uncertainty from hadronic form-factors, if we appropriately constrain kinematical regions of q2. We also give detailed analytical and numerical results on the differential decay width dΓ(B→K∗ℓ+ℓ−)/dq2, and the ratios of integrated branching fractions, B(B→ρℓ+ℓ−)/B(B→K∗ℓ+ℓ−). We estimate that one can determine the ratio Vts from those decays within theoretical accuracy of ∼10%.