Observation of $\eta_c(1S)\to \Sigma^0\bar \Sigma^0$ and search for $h_c(1P)\to \Sigma^0\bar \Sigma^0$ via $\psi(3686)$ transitions

TL;DR

This paper reports the first observation of the decay $ ext{eta}_c(1S) o ext{Sigma}^0 ar{ ext{Sigma}}^0$ via $ ext{psi}(3686)$ transitions, measuring its branching fraction and setting limits on the $h_c$ decay, using a large data sample from BESIII.

Contribution

First observation of $ ext{eta}_c(1S) o ext{Sigma}^0 ar{ ext{Sigma}}^0$ decay and measurement of its branching fraction, along with a search and upper limit for $h_c$ decay.

Findings

Branching fraction for $ ext{eta}_c(1S) o ext{Sigma}^0 ar{ ext{Sigma}}^0$ is approximately $2.59 imes 10^{-3}$ under destructive interference.

No significant signal for $h_c o ext{Sigma}^0 ar{ ext{Sigma}}^0$, upper limit set at $1.02 imes 10^{-4}$.

Decay observed for the first time with dependence on interference pattern.

Abstract

Using $(2712.4 \pm 14.3) \times 10^6~\psi(3686)$ events collected by the BESIII detector operating at the BEPCII collider, the hadronic decay $\eta_{c}\to\Sigma^{0}\bar{\Sigma^{0}}$ is observed for the first time via the radiative transition from $\psi(3686)$. It is found that the branching fraction has a significant dependence on the interference pattern between $\eta_c(1S)$ and non-$\eta_c(1S)$ processes. They are determined to be $\displaystyle\mathcal{B}(\eta_c(1S) \to \Sigma^{0}\bar{\Sigma^{0}}) = (2.59 \pm 0.14(stat) \pm 0.44(syst)) \times 10^{-3}$ and $(1.18 \pm 0.12(stat) \pm 0.21(syst)) \times 10^{-3}$, for the destructive and constructive interference scenarios, respectively. No significant signal is observed for the decay $h_{c}\to\Sigma^{0}\bar{\Sigma^{0}}$ in the hadronic transition $\psi(3686)\to\pi^0h_{c}$, and an upper limit on its branching fraction is set to be $1.02\times 10^{-4}$ at the 90\% confidence level.