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Study of Charmonium Decays into Baryon-Antibaryon Pairs

K. Abe
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Abstract

We study the baryonic charmonium decays of $B$ mesons, $B^+ \to η_c K^+$ and $B^+ \to J/ψK^+$, where $η_c$ and $J/ψ$ subsequently decay into a $p\bar p$ or $Λ\barΛ$ pair. The charmonium produced in the above $B$ meson decays is fully polarized. The polar angular distributions of the baryon-antibaryon pairs are presented, along with fit results to a $1 + α_B\cos^2θ$ parametrization. Comparisons are made with the results from $e^+e^- \to J/ψ$ formation experiments. We also report the firstobservation of $η_c \to Λ\bar\Lambdar$. The measured branching fraction is ${\mathcal B}(η_c \to Λ\barΛ) = (0.87^{+0.24}_{-0.21} \pm 0.14 \pm 0.27) \times 10^{-3}$. This study is based on a $357~fb^{-1}$ data sample recorded on the $Υ({\rm 4S})$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.

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K. Abe. 2005-09-16. Study of Charmonium Decays into Baryon-Antibaryon Pairs. https://arxiv.org/abs/hep-ex/0509020

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