${{\mathit \Upsilon}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}{(1S)}}$  Decay Mode Summary INSPIRE   PDGID:
M052.111
Mode (*) Fraction ($\Gamma_i$ / $\Gamma$) Scale Factor/
Conf. Level		 P(MeV/c)  
$\Gamma_{78}$ ${{\mathit \Upsilon}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}{(1S)}}$ $<2.7 \times 10^{-5}$ CL= 90% 4568
Category: Radiative decays
The following data is related to the above value:
$\Gamma($ ${{\mathit \Upsilon}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \eta}_{{{c}}}{(1S)}})/\Gamma_{\text{total}}$
$\Gamma_{78}/\Gamma$