Observation of $\psi(3686) \rightarrow e^{+}e^{-}\chi_{cJ}$ and $\chi_{cJ} \rightarrow e^{+}e^{-}J/\psi$

Abstract

Using 4.479×108 ψ(3686) events collected with the BESIII detector, we search for the decays ψ(3686)→e+e−χc0,1,2 and χc0,1,2→e+e−J/ψ. The decays ψ(3686)→e+e−χc0,1,2 and χc0,1,2→e+e−J/ψ are observed for the first time. The measured branching fractions are B(ψ(3686)→e+e−χc0,1,2)=(11.7±2.5±1.0)×10−4, (8.6±0.3±0.6)×10−4, (6.9±0.5±0.6)×10−4, and B(χc0,1,2→e+e−J/ψ)=(1.51±0.30±0.13)×10−4, (3.73±0.09±0.25)×10−3, (2.48±0.08±0.16)×10−3. The ratios of the branching fractions B(ψ(3686)→e+e−χc0,1,2)B(ψ(3686)→γχc0,1,2) and B(χc0,1,2→e+e−J/ψ)B(χc0,1,2→γJ/ψ) are also reported.