Measurement of branching fractions for $\psi (3686)\to \gamma {\eta }^{\prime },\gamma \eta$ and $\gamma {\pi }^0$

M. Ablikim, M. N. Achasov, X. C. Ai +420

Using a data sample of $448\times 10^6$ $\psi (3686)$ events collected with the BESIII detector operating at the BEPCII storage ring, the decays $\psi (3686)\to \gamma \eta$ and $ψ(3686)\ri…