Observation of the $J/\psi$ and $\psi(3686)$ decays into $\eta\Sigma^{+}\bar{\Sigma}^{-}$

TL;DR

This paper reports the first observation of specific decay modes of J/psi and psi(3686) particles into eta and Sigma baryons, measuring their branching fractions with high statistical significance.

Contribution

It provides the first measurement of these decay channels and compares their branching ratios, confirming consistency with the 12% rule in charmonium decays.

Findings

First observation of the decay modes.

Measured branching fractions with statistical and systematic uncertainties.

Branching ratio ratio consistent with the 12% rule.

Abstract

The decays $J/\psi\to\eta\Sigma^{+}\bar{\Sigma}{}^-$ and $\psi(3686)\to\eta\Sigma^{+}\bar{\Sigma}{}^-$ are observed for the first time, using $(10087 \pm 44)\times 10^{6}$ $J/\psi$ and $(448.1 \pm 2.9)\times 10^{6}$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII collider. We determine the branching fractions of these two decays to be ${\cal B}(J/\psi\to\eta\Sigma^{+}\bar{\Sigma}{}^-)=(6.34 \pm 0.21 \pm 0.37)\times 10^{-5}$ and ${\cal B}(\psi(3686)\to\eta\Sigma^{+}\bar{\Sigma}{}^-)=(9.59 \pm 2.37 \pm 0.61)\times 10^{-6}$, where the first uncertainties are statistical and the second are systematic. The ratio of these two branching fractions is determined to be $\frac{{\cal B}(\psi(3686)\to\eta\Sigma^{+}\bar{\Sigma}{}^-)}{{\cal B}(J/\psi\to\eta\Sigma^{+}\bar{\Sigma}{}^-)}=(15.1 \pm 3.8)\%$, which is in agreement with the "12\% rule."