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

Abstract

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 experimentin 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: B(B0→J/ψω)B(B0→J/ψρ0)=0.89±0.19(stat)+0.07−0.13(syst),B(B0s→J/ψη)B(B0→J/ψρ0)=14.0±1.2(stat)+1.1−1.5(syst)+1.1−1.0(fdfs),B(B0s→J/ψη′)B(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 thataccounts 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 B(B0s→J/ψη′)B(B0s→J/ψη)=0.90±0.09(stat)+0.06−0.02(syst).