Observation of $J/\psi\phi$ structures consistent with exotic states   from amplitude analysis of $B^+\to J/\psi \phi K^+$ decays
  The first full amplitude analysis of $B^+\to J/\psi \phi K^+$ with $J/\psi\to\mu^+\mu^-$, $\phi\to K^+K^-$ decays is performed with a data sample of 3 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}=7$ and $8$ TeV with the LHCb detector. The data cannot be described by a model that contains only excited kaon states decaying into $\phi K^+$, and four $J/\psi\phi$ structures are observed, each with significance over $5$ standard deviations. The quantum numbers of these structures are determined with significance of at least $4$ standard deviations. The lightest has mass consistent with, but width much larger than, previous measurements of the claimed $X(4140)$ state. 
LHCb collaboration: R. Aaij, B. Adeva, M. Adinolfi, Z. Ajaltouni, S.   Akar, J. Albrecht, F. Alessio, M. Alexander, S. Ali, ...
hep-ex