Quantum correlation of neutral charmed mesons at BESIII

BESIII has recently accumulated a large data sample near the $\psi (3770)$ production threshold corresponding to an integrated luminosity of $20{\text{ fb}}^{-1}$. Neutral $D^0{\bar{D}}^0$ pairs produced at the $\psi (3770)$ are in a $C$-odd correlated state, providing a unique laboratory to measure the strong-phase differences between $D^0$ and ${\bar{D}}^0$ decays. These parameters are essential inputs to the study of CP violation in heavy-flavor physics, primarily in the determinations of the CKM angle gamma and charm-mixing parameters. These proceedings report new measurements of strong-phase differences in different neutral $D$ decays at BESIII, including new measurements of the strong phases in $D\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ decays. Additionally reported is the first observation of correlated $DD$ pairs produced at $e^{+}{e}^{-}$ center-of-mass energies above the $\psi (3770)$ threshold, where $e^{+}{e}^{-}\to D^{\ast }\bar{D}$ and $e^{+}{e}^{-}\to D^{\ast }{\bar{D}}^{\ast }$ processes also occur. These processes produce both $C$-odd and $C$-even correlated $D^0{\bar{D}}^0$ pairs, which allow for new measurement techniques to determine strong-phases from previously unused datasets.