Amplitude Analysis of the Decay B̅⁰ → Ks⁰π⁺π⁻ and First Observation of the CP Asymmetry in B̅⁰ → K* (892)⁻π⁺

The time-integrated untagged Dalitz plot of the three-body hadronic charmless decay (B) over bar (0) -> K-S(0)pi(+)pi(-) is studied using a pp collision data sample recorded with the LHCb detector, corresponding to an integrated luminosity of 3.0 fb(-1). The decay amplitude is described with an isobar model. Relative contributions of the isobar amplitudes to the (B) over bar (0) -> K-S(0)pi(+)pi(-) decay branching fraction and CP asymmetries of the flavor-specific amplitudes are measured. The CP asymmetry between the conjugate (B) over bar (0) -> K* (892)(-)pi(+) and (B) over bar (0) -> K* (892)(-)pi(+) decay rates is determined to be -0.308 +/- 0.062.