${{\mathit \eta}_{{{c}}}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$  Decay Mode Summary INSPIRE   JSON  (beta) PDGID:
M059.21
Mode Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/
Conf. Level
P(MeV/c)  
$\Gamma_{23}$ ${{\mathit \eta}_{{{c}}}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$ $<0.018$ CL= 90% 501
The following data is related to the above value: