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