${{\mathit \eta}_{{c}}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$   Decay Mode Summary INSPIRE   PDGID:
M059.21
Mode Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/
Conf. Level		 P(MeV/c)  
$\Gamma_{17}$ ${{\mathit \eta}_{{c}}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$ $<0.014$ CL= 90% 501
The following data is related to the above value:
$\Gamma($ ${{\mathit \eta}_{{c}}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$ $)/\Gamma_{\text{total}}{\times }$ $\Gamma($ ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{c}}{(2S)}}$ $)/\Gamma_{\text{total}}$
$\Gamma_{17}/\Gamma{\times }\Gamma^{{{\mathit \psi}{(2S)}}}_{170}/\Gamma^{{{\mathit \psi}{(2S)}}}$