Evidence for a Narrow Near-Threshold Structure in the $J/\psi \varphi$ Mass Spectrum in $B^{+}\to J/\psi \varphi K^{+}$ Decays

The CDF Collaboration, T. Aaltonen

Evidence is reported for a narrow structure near the $J/\psi \varphi$ threshold in exclusive $B^{+}\to J/\psi \varphi K^{+}$ decays produced in $\bar{p}p$ collisions at $\sqrt{s}=1.96 \TeV$. A signal of…