Search for di-photon decays of an axion-like particle in radiative $J/\ddot{I}ˆ$ decays

Abstract

We search for the di-photon decay of a light pseudoscalar axion-like particle, $a$, in radiative $J/\ddot{I}ˆ$ decays, using 10 billion $J/\ddot{I}ˆ$ 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 $\mathcal{B}(J/\ddot{I}ˆ\to {\hat{I}}^{3}a)\times \mathcal{B}(a\to {\hat{I}}^3{\hat{I}}^3)$ and the axion-like particle photon coupling constant $g_{a{\hat{I}}^3{\hat{I}}^3}$ in the ranges of $(3.7-48.5)\times 10^{-8}$ and $(2.2-101.8)\times 10^{-4}$ GeV${}^{-1}$, respectively, for $0.18\le m_a\le 2.85$ GeV/$c^2$. These are the most stringent limits to date in this mass region.

9 pages, 5 figures, Published in Phys. Rev. D 110, L031101 (2024)