Measurement of the ratio B(Bs0→J/ψf0(980))/B(Bs0→J/ψϕ(1020)) in pp collisions at s=7 TeV

Abstract A measurement of the ratio of the branching fractions of the B s 0 meson to J / ψ f 0 ( 980 ) and to J / ψ ϕ ( 1020 ) is presented. The J / ψ , f 0 ( 980 ) , and ϕ ( 1020 ) are observed through their decays to μ + μ − , π + π − , and K + K − , respectively. The f 0 and the ϕ are identified by requiring | M π + π − − 974  MeV | 50  MeV and | M K + K − − 1020  MeV | 10  MeV . The analysis is based on a data sample of pp collisions at a centre-of-mass energy of 7 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 fb−1. The measured ratio is B ( B s 0 → J / ψ f 0 ) B ( f 0 → π + π − ) B ( B s 0 → J / ψ ϕ ) B ( ϕ → K + K − ) = 0.140 ± 0.008 ( stat ) ± 0.023 ( syst ) , where the first uncertainty is statistical and the second is systematic.