Measurement of the B 0s → ϕϕ branching fraction and search for the decay B 0 → ϕϕ

Abstract

Using a dataset corresponding to an integrated luminosity of 3.0 fb−1 collected in pp collisions at centre-of-mass energies of 7 and 8 TeV, the B 0s → ϕϕ branching fraction is measured to be

B(B0s→ϕϕ)=(1.84±0.05(stat)±0.07(syst)±0.11(fs/fd)±0.12(norm))×10−5, where f s /f d represents the ratio of the B 0s to B 0 production cross-sections, and the B 0 → ϕK *(892)0 decay mode is used for normalization. This is the most precise measurement of this branching fraction to date, representing a factor five reduction in the statistical uncertainty compared with the previous best measurement. A search for the decay B 0 → ϕϕ is also made. No signal is observed, and an upper limit on the branching fraction is set as

B(B0→ϕϕ)<2.8×10−8 at 90% confidence level. This is a factor of seven improvement compared to the previous best limit.