“…The processes J/ψ → γη ′ with η ′ → γγ, η ′ → γe + e − and η ′ → γρ 0 , ρ 0 → e + e − may contribute peaking backgrounds to the invariant mass M (e + e − e + e − ) distributions, if the photons subsequently convert into e + e − pairs in the beam pipe or the inner wall of the MDC. To distinguish the γ conversion events from signal events, the Photon Conversion Finder package [22,23] IP in the transverse plane. Here, R x and R y represent the coordinates of the reconstructed vertex position in the x and y directions.…”