Observation of 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 the observation of a narrow structure near the $J/\u03a6$ threshold in $B^+ o J/\u03a6 K^+$ decays, indicating a potential new hadronic state with high statistical significance.

Contribution

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

Findings

Structure observed with >5 sigma significance

Mass spectrum shows a narrow near-threshold peak

Potential indication of a new exotic hadron state

Abstract

Observation is reported for a structure near the $J/\psi\phi$ threshold in $B^+\rightarrow J/\psi\phi K^+$ decays produced in $\bar{p} p $ collisions at $\sqrt{s}=1.96 \TeV$ with a statistical significance of beyond 5 standard deviations.