Rare B Decays into States Containing a J/psi Meson and a Meson with ssbar Quark Content

We report a study of the B meson decays, B+ -> J/psi phi K+, B0 -> J/psi phi K0S, B0 -> J/psi phi, B0 -> J/psi eta and B0 -> J/psi eta' using 56 million BBbar events collected at the Y(4S) resonance with the BABAR detector at the PEP-II e+ e- asymmetric-energy storage ring. We measure the branching fractions B(B+ -> J/psi phi K+) = (4.4 +- 1.4(stat) +- 0.5(syst)) * 10-5 and B(B0 -> J/psi phi K0S) = (5.1 +- 1.9(stat) +- 0.5(syst)) * 10^-5, and set upper limits at 90% confidence level for the branching fractions B(B0 -> J/psi phi) < 9.2 * 10^-6, B(B0 -> J/psi eta)< 2.7 * 10^-5, and B(B0 -> J/psi eta')< 6.3 * 10-5.