Observation of the decays $\chi_{cJ}\to n K^{0}_{S}\bar\Lambda + c.c.$

TL;DR

This study reports the first observation of specific $ ext{chi}_{cJ}$ decays into a neutron, $K_S^0$, and an anti-Lambda, using a large sample of $ ext{psi}(3686)$ events collected with BESIII, and measures their branching fractions.

Contribution

First observation of $ ext{chi}_{cJ} o n K_S^0 ar{ ext{Lambda}} + c.c.$ decays and measurement of their branching fractions.

Findings

Branching fractions for $J=0,1,2$ are measured.

Decays observed for the first time.

Results provide new insights into charmonium decay modes.

Abstract

By analyzing $4.48\times10^8$ $\psi(3686)$ events collected with the BESIII detector, we observe the decays $\chi_{cJ} \to n K^0_S\bar\Lambda + c.c.$ ($J=0$, 1, 2) for the first time, via the radiative transition $\psi(3686) \to \gamma \chi_{cJ}$. The branching fractions are determined to be $(6.67 \pm 0.26_{\rm stat} \pm 0.41_{\rm syst})\times10^{-4}$, $(1.71 \pm 0.12_{\rm stat} \pm 0.12_{\rm syst})\times10^{-4}$, and $(3.66 \pm 0.17_{\rm stat} \pm 0.23_{\rm syst})\times10^{-4}$ for $J=0$, 1, and 2, respectively.