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

Abstract : Evidence is reported for a narrow structure near the $J/\psi\phi$ threshold in exclusive $B^+\to J/\psi\phi K^+$ decays produced in $\bar{p} p$ collisions at $\sqrt{s}=1.96 \TeV$. A signal of $14\pm5$ events, with statistical significance in excess of 3.8 standard deviations, is observed in a data sample corresponding to an integrated luminosity of $2.7 \ifb$, collected by the CDF II detector. The mass and natural width of the structure are measured to be $4143.0\pm2.9(\mathrm{stat})\pm1.2(\mathrm{syst}) \MeVcc$ and $11.7^{+8.3}_{-5.0}(\mathrm{stat})\pm3.7(\mathrm{syst}) \MeVcc$.
Document type :
Preprints, Working Papers, ...

http://hal.in2p3.fr/in2p3-00368052
Contributor : Swarna Bassava <>
Submitted on : Friday, March 13, 2009 - 2:31:03 PM
Last modification on : Tuesday, December 8, 2020 - 3:45:55 AM

### Identifiers

• HAL Id : in2p3-00368052, version 1
• ARXIV : 0903.2229

### Citation

T. Aaltonen, J. Adelman, T. Akimoto, B. Alvarez Gonzalez, S. Amerioy, et al.. Evidence for a Narrow Near-Threshold Structure in the $J/\psi\phi$ Mass Spectrum in $B^+\to J/\psi\phi K^+$ Decays. 2009. ⟨in2p3-00368052⟩

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