First Observation of the Decay $B\to J/ψφK$

We present the first observation of the decay B->J/psi phi K. Using 9.6 million B meson pairs collected with the CLEO detector, we have observed 10 fully reconstructed B->J/psi phi K candidates, whereas the estimated mean background is 0.5 events. We obtained Br(B->J/psi phi K) = (8.8+3.5/-3.0(stat)+/-1.3(syst))*10^-5. This observation serves as the first conclusive evidence for the $s \bar{s}$ pair popping in the B meson decays.