Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of B0s meson decays to J/ψη and J/ψη′

First evidence of the B0→J/ψω decay is found and the B0s→J/ψη and B0s→J/ψη′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of s√=7 TeV. The branching fractions of these decays are measured relative to that of the B0→J/ψρ0 decay:
Br(B0→J/ψω)Br(B0→J/ψρ0)=0.89±0.19(stat)+0.07−0.13(syst)
Br(B0s→J/ψη)Br(B0→J/ψρ0)=14.0±1.2(stat)+1.1−1.5(syst)+1.1−1.0(fdfs),
Br(B0s→J/ψη′)Br(B0→J/ψρ0)=12.7±1.1(stat)+0.5−1.3(syst)+1.0−0.9(fdfs),
where the last uncertainty is due to the knowledge of fd/fs, the ratio of b-quark hadronization factors that accounts for the different production rate of B0 and B0s mesons. The ratio of the branching fractions of B0s→J/ψη′ and B0s→J/ψη decays is measured to be
Br(B0s→J/ψη′)Br(B0s→J/ψη)=0.90±0.09(stat)+0.06−0.02(syst).