Search for C-parity violation in J/ψ → γγ and γφ

Using 1.06 × 10⁸ψ (3686) events recorded in e⁺e^-, collisions at √s = 3.686 GeV with the BESIII at the BEPCII collider, we present searches for C-parity violation in J/ψ → γγ and γφ decays via ψ(3686) → J/ψπ⁺π^-. No significant signals are observed in either channel. Upper limits on the branching fractions are set to be B(J/ψ → γγ) < 2.7 × 10^-7, and B(J/ψ → γφ>) < 1.4 × 10^-6, at the 90% confidence level. The former is one order of magnitude more stringent than the previous upper limit, and the latter represents the first limit on this decay channel.