First observations of $ψ(2S)$ and $χ_{cJ}(1P)$ decays to four-body final states $h^+h^- K^0_S K^0_S$

Abstract

$χ_{c0}$, $χ_{c1}$, and $χ_{c2}$ decays to $π^+π^-K^0_SK^0_S$ and $K^+K^-K^0_SK^0_S$, as well as $ψ(2S)$ decay to $π^+π^-K^0_SK^0_S$ are presented. The branching fractions of these decay channels are determined using $14\times 10^6$ $ψ(2S)$ events collected at BESII/BEPC. The branching fractions of $χ_{c0},χ_{c2}\to K^0_SK^0_S$ are measured with improved statistical precision.