Amplitude analysis of B_s⁰ → K_S⁰ K ^± π ^∓ decays

The first untagged decay-time-integrated amplitude analysis of B_s⁰ → K_S⁰K^±π^∓ decays is performed using a sample corresponding to 3.0 fb⁻¹ of pp collision data recorded with the LHCb detector during 2011 and 2012. The data are described with an amplitude model that contains contributions from the intermediate resonances K^*(892)^0,+, K₂^*(1430)^0,+ and K₀^*(1430)^0,+, and their charge conjugates. Measurements of the branching fractions of the decay modes B_s⁰ → K^*(892)^±K^∓ and Bs0→K*(—)(892)0K0(—) are in agreement with, and more precise than, previous results. The decays B_s⁰ → K₀^*(1430)^±K^∓ and Bs0→K0*(—)(1430)0K0(—) are observed for the first time, each with significance over 10 standard deviations.