Studies of the decays B⁺→pp̄h⁺ and observation of B⁺→Λ̄(1520)p

Dynamics and direct CP violation in three-body charmless decays of charged B mesons to a proton, an antiproton and a light meson (pion or kaon) are studied using data, corresponding to an integrated luminosity of 1.0 fb ^-1, collected by the LHCb experiment in pp collisions at a center-of-mass energy of 7 TeV. Production spectra are determined as a function of Dalitz-plot and helicity variables. The forward-backward asymmetry of the light meson in the pp̄ rest frame is measured. No significant CP asymmetry in B ⁺→pp̄K ⁺ decay is found in any region of the Dalitz plane. We present the first observation of the decay B ⁺→Λ̄(1520)(→K ⁺p̄)p near the K ⁺p̄ threshold and measure B(B ⁺→Λ̄ (1520)p)=(3.9-0.9+1.0(stat)±0.1(syst)±0.3(BF))×10 ^-7, where BF denotes the uncertainty on secondary branching fractions.