B_s→K^(∗)ℓν-bar, angular analysis, S-wave contributions and |V_ub|

We analyse the B-bar_s⁰→K⁺l⁻ν-bar and B-bar_s⁰→K^∗+(→Kπ)ℓ⁻ν-bar decays that are valuable for extracting the CKM matrix element |V_ub|. We calculate the differential and integrated partial widths in units of |V_ub|² based on various calculations of hadronic form factors and in particular the latest Lattice QCD calculation of the B_s→K^∗ form factors. For the decay B-bar_s⁰→Kπℓν-bar, we formulate the general angular distributions with the inclusion of the various partial-wave Kπ contributions. Using the results for the Kπ scalar form factor calculated from unitarized chiral perturbation theory, we explore the S-wave effects on angular distribution variables and demonstrate that they may not be negligible, considering the high precision expected in future measurements. We also briefly discuss the impact of the S-wave ππ contributions in the B⁻→π⁺π⁻ℓν-bar decay and provide estimates for the mode B⁻→K⁺K⁻ℓν-bar. The studies of these channels in future can not only be used to determine |V_ub|, but may also provide valuable information on the Kπ and ππ phase shifts