Search for CP violation in Ξ−b→pK−K− decays

Abstract

A search for CP violation in charmless three-body Ξ−b→pK−K− decays is performed using pp collision data recorded with the LHCb detector, corresponding to integrated luminosities of 1 fb−1 at a center-of-mass energy √s=7 TeV, 2 fb−1 at √s=8 TeV and 2 fb−1 at √s=13 TeV. A good description of the phase-space distribution is obtained with an amplitude model containing contributions from Σ(1385), Λ(1405), Λ(1520), Λ(1670), Σ(1775) and Σ(1915) resonances. The model allows for CP -violation effects, which are found to be consistent with zero. The branching fractions of Ξ−b→Σ(1385)K−, Ξ−b→Λ(1405)K−, Ξ−b→Λ(1520)K−, Ξ−b→Λ(1670)K−, Ξ−b→Σ(1775)K− and Ξ−b→Σ(1915)K− decays are also reported. In addition, an upper limit is placed on the product of ratios of Ω−b and Ξ−b fragmentation fractions and the Ω−b→pK−K− and Ξ−b→pK−K− branching fractions.