We present a study of the process $e^+e^-\to\pi^{ \pm}(D\bar{ D}^*)^{ \mp}$ using data samples of 1092~pb$^{ -1}$ at $\sqrt{ s}=4.23$~GeV and 826~pb$^{ -1}$ at $\sqrt{ s}=4.26$~GeV collected with the BESIII detector at the BEPCII storage ring. With full reconstruction of the $D$ meson pair and the bachelor $\pi^{ \pm}$ in the final state, we confirm the existence of the charged structure $Z_c(3885)^{ \mp}$ in the $(D\bar{ D}^*)^{ \mp}$ system in the two isospin processes $e^+e^-\to\pi^+D^0D^{ *-}$ and $e^+e^-\to\pi^+D^-D^{ *0}$. By performing a simultaneous fit, the statistical significance of $Zc(3885)^{ \mp}$ signal is determined to be greater than 10$\sigma$, and its pole mass and width are measured to be $M_{ \rm{ pole}}$=(3881.7$\pm$1.6(stat.)$\pm$1.6(syst.))~MeV/$c^2$ and $\Gamma_{ \rm{ pole}}$=(26.6$\pm$2.0(stat.)$\pm$2.1(syst.))~MeV, respectively. The Born cross section times the $(D\bar{ D}^*)^{ \mp}$ branching fraction ($\sigma(e^+e^-\to\pi^{ \pm}Z_{ c}(3885)^{ \mp}) \times Br(Z_{ c}(3885)^{ \mp}\to(D\bar{ D}^*)^{ \mp})$) is measured to be $(141.6\pm7.9(\text{ stat.})\pm12.3(\text{ syst.}))~\text{ pb}$ at $\sqrt{ s}=4.23$~GeV and $(108.4\pm6.9(\text{ stat.})\pm8.8(\text{ syst.}))~\text{ pb}$ at $\sqrt{ s}=4.26$~GeV. The polar angular distribution of the $\pi^{ \pm}$-$Z_c(3885)^{ \mp}$ system is consistent with the expectation of a quantum number assignment of $J^P=1^+$ for $Z_c(3885)^{ \mp}$.
Categories: hep-ex