  Observation is reported for a structure near the $J/\psi\phi$ threshold in $B^+\rightarrow J/\psi\phi K^+$ decays produced in $\bar{p} p $ collisions at $\sqrt{s}=1.96 \TeV$ with a statistical significance of beyond 5 standard deviations. 
Observation of a Narrow Near-Threshold Structure in the $J/\psi\phi$   Mass Spectrum in $B^+\to J/\psi\phi K^+$ Decays