Search for di-photon decays of an axion-like particle in radiative J/ψ decays

We search for the di-photon decay of a light pseudoscalar axion-like particle, a, in radiative J/\psi decays, using 10 billion J/\psi events collected with the BESIII detector. We find no evidence of a signal and set upper limits at the 95\% confidence level on the product branching fraction $\mathcal{B}(J/\psi \to... Show more