Measurement of Branching Fractions of $J/\psi$ and $\psi(3686)$ decays to $\Sigma^{+}$ and $\overline{\Sigma}^-$

TL;DR

This study precisely measures the branching fractions of $J/3$ and $368$ decays to $ ext{Sigma}^{+} ext{Sigma}^{-}$ using large data samples, revealing a significant violation of the expected $12 ext{ ext{ extperthousand}}$ rule.

Contribution

It provides the first precise measurements of these decay modes and demonstrates a notable deviation from the $12 ext{ ext{ extperthousand}}$ rule, challenging existing theoretical expectations.

Findings

Branching fraction of $J/3$ decay: $(10.61 \u00b1 0.04 \u00b1 0.36) imes 10^{-4}$

Branching fraction of $368$ decay: $(2.52 \u00b1 0.04 \u00b1 0.09) imes 10^{-4}$

Decay ratio violates the $12 ext{ ext{ extperthousand}}$ rule at $(23.8 \u00b1 1.1) ext{ ext{ extperthousand}}$

Abstract

Using $1310.6\times10^{6}$ $J/\psi$ and $448.1\times10^{6}$ $\psi(3686)$ events collected with the BESIII detector, the branching fractions of $J/\psi$ and $\psi(3686)$ decays to $\Sigma^{+}\overline{\Sigma}^{-}$ are measured to be $(10.61 \pm 0.04 \pm 0.36) \times 10^{-4}$ and $(2.52 \pm 0.04 \pm 0.09) \times 10^{-4}$, respectively. In addition, the ratio of $\mathcal{B}(\psi(3686) \rightarrow \Sigma^{+}\overline{\Sigma}^{-})/\mathcal{B}(J/\psi \rightarrow \Sigma^{+}\overline{\Sigma}^{-})$ is determined to be $(23.8 \pm 1.1)\%$ which violates the "$12\%$ rule".