${{\mathit J / \psi}{(1S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$  Decay Mode Summary INSPIRE   PDGID:
M070.259
Mode (*) Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/
Conf. Level		 P(MeV/c)  
$\Gamma_{354}$ ${{\mathit J / \psi}{(1S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}}$ $<7.8 \times 10^{-7}$ CL= 90%
Category: Radiative decays
Note: For a narrow scalar or pseudoscalar ${{\mathit A}^{0}}$ with mass $0.21 - 3.0$ GeV.
The following data is related to the above value:
$\Gamma($ ${{\mathit J / \psi}{(1S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit A}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \mu}^{+}}{{\mathit \mu}^{-}})/\Gamma_{\text{total}}$
$\Gamma_{354}/\Gamma$