Quite some time ago I discussed here
the tentative Y(4140) resonance claimed by the CDF collaboration in their Run II data. This was a peak which was found in B-decay data containing a J/Psi signal, a phi meson, and an additional kaon track, and it resulted from the study of the mass difference of the J/Psi + phi signal and the J/Psi alone.
Confused ? You have all rights to be. I will explain everything in good order, but be sure that the matter was puzzling not only for laymen but also for insiders: because the find was mysterious, not predicted by existing models, and potentially controversial.B Decays and the CDF Claim