Observation of $K^*(892)^0\bar K^*(892)^0$ in $χ_{cJ}$ Decays

Abstract

$K^*(892)^0\bar K^*(892)^0$ signals from $χ_{cJ} (J=0,1,2)$ decays are observed for the first time using a data sample of 14 million $ψ(2S)$ events accumulated at the BES II detector. The branching fractions ${\cal B}(χ_{cJ}\to K^*(892)^0\bar K^*(892)^0)$ $(J = 0,1,2)$ are determined to be $(1.55 \pm 0.35 \pm 0.30)\times 10^{-3}$, $(1.58 \pm 0.32 \pm 0.29)\times 10^{-3}$, and $(4.67 \pm 0.55 \pm 0.85)\times 10^{-3}$ for the $χ_{c0}$, $χ_{c1}$ and $χ_{c2}$ decays, respectively, where the first errors are statistical and the second are systematic. The significances of these signals are about 4.2$σ$, 4.3$σ$, and 7.5$σ$, respectively.