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

TL;DR

This paper reports evidence for a narrow resonance near the $J/\u03a6$ threshold in $B^+ o J/\u03a6 K^+$ decays, observed in proton-antiproton collisions, with a significance over 3.8 sigma and measured mass and width.

Contribution

First evidence of a narrow near-threshold structure in the $J/\u03a6$ spectrum from $B^+$ decays in proton-antiproton collisions.

Findings

Observed a structure with 14±5 events.

Mass measured at 4143.0±2.9(stat)±1.2(syst) MeV/c².

Width measured at 11.7^{+8.3}_{-5.0}(stat)±3.7(syst) MeV/c².

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 $11.7^{+8.3}_{-5.0}(\mathrm{stat})\pm3.7(\mathrm{syst}) \MeVcc$.