Observation of $χ_{cJ}\to4K_{S}^{0}$

Abstract

By analyzing $(448.1\pm2.9)\times10^6$ $ψ(3686)$ events collected with the BESIII detector operating at the BEPCII collider, the decays of $χ_{cJ} \to 4K_S^0$ ($J=0,1,2$) are observed for the first time with statistical significances of 26.5$σ$, 5.9$σ$ and 11.4$σ$, respectively. The product branching fractions of $ψ(3686)\toγχ_{cJ}$, $χ_{cJ}\to4K_{S}^{0}$ are presented and the branching fractions of $χ_{cJ}\to4K_{S}^{0}$ decays are determined to be $\mathcal{B}_{χ_{c0}\to 4K_S^0}$=$(5.76\pm0.34\pm0.38)$$\times10^{-4}$, $\mathcal{B}_{χ_{c1}\to 4K_S^0}$=$(0.35\pm0.09\pm0.03)$$\times10^{-4}$ and $\mathcal{B}_{χ_{c2}\to 4K_S^0}$=$(1.14\pm0.15\pm0.08)$$\times10^{-4}$, where the first uncertainties are statistical and the second are systematic, respectively.