Observation of $h_c$ radiative decay $h_c\to \gamma {\eta }^{\prime }$ and evidence for $h_c\to \gamma \eta$

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

A search for radiative decays of the $P$-wave spin singlet charmonium resonance $h_c$ is performed based on $4.48\times 10^8$ ${\psi }^{\prime }$ events collected with the BESIII detector ope…