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A broad peak observed at ${{\mathit K}^{+}}{{\mathit K}^{-}}$ invariant mass. Mass and width above are its pole position. The observed branching ratio is B( ${{\mathit J / \psi}}$ $\rightarrow$ ${{\mathit X}}{{\mathit \pi}^{0}}$ ) B( ${{\mathit X}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}$ ) = ($8.5$ $\pm0.6$ ${}^{+2.7}_{-3.6}$) $ \times 10^{-4}$.
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