First observation of B + → Ds + K + K − decays and a search for B + → Ds + ϕ decays

Abstract

A search for B+ → D+ s K+K− decays is performed using pp collision data corresponding to an integrated luminosity of 4.8 fb−1 , collected at centre-of-mass energies of 7, 8 and 13 TeV with the LHCb experiment. A significant signal is observed for the first time and the branching fraction is determined to be B(B + → D+ s K+K−) = (7.1 ± 0.5 ± 0.6 ± 0.7) × 10−6 , where the first uncertainty is statistical, the second systematic and the third due to the uncertainty on the branching fraction of the normalisation mode B+ → D+ sD 0 . A search is also performed for the pure annihilation decay B+ → D+ s φ. No significant signal is observed and a limit of B(B + → D+ s φ) < 4.9 × 10−7 (4.2 × 10−7 ) is set on the branching fraction at 95% (90%) confidence level. Keywords: B physics, Branching fraction, Hadron-Hadron scattering (experiments), Rare decay