Measurement of the B {/s 0} → 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 B0 s → φφ branching fraction is measured to be B(B 0 s → φφ) = (1.84 ± 0.05 (stat) ± 0.07 (syst) ± 0.11 (fs/fd) ± 0.12 (norm) )×10−5 , where fs/fd represents the ratio of the B0 s to B0 production cross-sections, and the B0 → 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 B0 → φφ is also made. No signal is observed, and an upper limit on the branching fraction is set as B(B 0 → φφ) < 2.8 × 10−8 at 90% confidence level. This is a factor of seven improvement compared to the previous best limit.