1
Statistical and systematic errors combined. From a fit with floating $\mathit M2$ amplitudes $\mathit a_{2}$ and $\mathit b_{2}$, and fixed $\mathit E3$ amplitudes $\mathit a_{3}=\mathit b_{3}$=0. Not independent of values for $\mathit a_{2}({{\mathit \chi}_{{{c2}}}{(1P)}}$) and $\mathit b_{2}({{\mathit \chi}_{{{c2}}}{(1P)}}$) from ARTUSO 2009.
References:
ARTUSO
2009
PR D80 112003
Higher-Order Multipole Amplitudes in Charmonium Radiative Transitions