Observation of the $\psi (1^3{D}_2)$ state in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\gamma {\chi }_{c1}$ at BESIII

M. Ablikim, M. N. Achasov, X. C. Ai +409

We report the observation of the $X(3823)$ in the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}X(3823)\to {\pi }^{+}{\pi }^{-}\gamma {\chi }_{c1}$ with a statistical significance of $6.2\sigma$, in data samples at center-of-mass e…