Angular analysis of the $e^{+}{e}^{-}\to D^{(\ast )\pm }{D}^{\ast \mp }$ process near the open charm threshold using initial-state radiation

We report a new measurement of the exclusive $e^+ e^- \to D^{() \pm} D^{\mp}$crosssectionsasafunctionofthecenter-of-massenergyfromthe$D^{() \pm} D^{ \mp}$thresholdthrough$\sqrt{s}=6.0$ GeV with initial-state radiation. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of $951$ fb${}^{-1}$. The accuracy of the cross section measurement is increased by a factor of two over the first Belle study. We perform the first angular analysis of the $e^+ e^- \to D^{* \pm} D^{* \mp}$ process and decompose this exclusive cross section into three components corresponding to the $D^{\ast }$ helicities.