Observation of several sources of CP violation in B⁺ →π⁺π⁺π^- decays

Observations are reported of different sources of CP violation from an amplitude analysis of B⁺ →π⁺π⁺π^- decays, based on a data sample corresponding to an integrated luminosity of 3 fb^-1 of pp collisions recorded with the LHCb detector. A large CP asymmetry is observed in the decay amplitude involving the tensor f₂(1270) resonance, and in addition significant CP violation is found in the π⁺π^-S wave at low invariant mass. The presence of CP violation related to interference between the π⁺π^-S wave and the P wave B⁺→ρ(770)⁰π⁺ amplitude is also established; this causes large local asymmetries but cancels when integrated over the phase space of the decay. The results provide both qualitative and quantitative new insights into CP -violation effects in hadronic B decays.