Observation of a Charged Charmoniumlike Structure in $e^+e^-\rightarrow D^0D^-\pi^++c.c.$
We present a partial wave analysis of the process $e^+e^- \rightarrow D^0 D^- \pi^++c.c.$ using a data sample collected with the BESIII detector at a center-of-mass energy of 4682~MeV. A charged structure, referred to as the $X(3790)^-$ near the $D^0D^-$ mass threshold with a significance of $5.3\sigma$, which includes systematic uncertainties and the look-elsewhere effect. Assuming a Flatt\'e description of the structure, the quantum numbers of the $X(3790)^-$ are found to be $J^{P}=1^{-}$, and its mass and coupling strength to the $D^0D^-$ channel are determined to be $(3794.7 \pm 6.0 \pm 8.7)$~MeV/$c^2$ and $(1.6 \pm 0.2 \pm 0.2)$~GeV, respectively, where the first uncertainties are statistical and the second systematic. In addition, we also report measurements of the masses and widths of the $D_{2}^{*}(2460)$, $D_{1}^{*}(2600)$, and $D_{1}^{*}(2760)$ charmed mesons.