Observation of B0s → χc1ϕ decay and study of B0 → χc1,2K⁎0 decays

Abstract The first observation of the decay B s 0 → χ c 1 ϕ and a study of B 0 → χ c 1 , 2 K ⁎ 0 decays are presented. The analysis is performed using a dataset, corresponding to an integrated luminosity of 1.0 fb −1 , collected by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. The following ratios of branching fractions are measured: B ( B s 0 → χ c 1 ϕ ) B ( B s 0 → J / ψ ϕ ) = ( 18.9 ± 1.8 (stat) ± 1.3 (syst) ± 0.8 ( B ) ) × 10 − 2 , B ( B 0 → χ c 1 K ⁎ 0 ) B ( B 0 → J / ψ K ⁎ 0 ) = ( 19.8 ± 1.1 (stat) ± 1.2 (syst) ± 0.9 ( B ) ) × 10 − 2 , B ( B 0 → χ c 2 K ⁎ 0 ) B ( B 0 → χ c 1 K ⁎ 0 ) = ( 17.1 ± 5.0 (stat) ± 1.7 (syst) ± 1.1 ( B ) ) × 10 − 2 , where the third uncertainty is due to the limited knowledge of the branching fractions of χ c → J / ψ γ modes.