Confirmation of a charged charmoniumlike state $Z_c(3885)^\mp$ in $e^+e^-\to\pi^\pm(D\barD^*)^\mp$ with double $D$ tag

摘要: We present a study of the process e+e−→π±(DD¯∗)∓ using data samples of 1092~pb−1 at s√=4.23~GeV and 826~pb−1 at 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 π± in the final state, we confirm the existence of the charged structure Zc(3885)∓ in the (DD¯∗)∓ system in the two isospin processes e+e−→π+D0D∗− and e+e−→π+D−D∗0. By performing a simultaneous fit, the statistical significance of Zc(3885)∓ signal is determined to be greater than 10σ, and its pole mass and width are measured to be Mpole=(3881.7±1.6(stat.)±1.6(syst.))~MeV/c2 and Γpole=(26.6±2.0(stat.)±2.1(syst.))~MeV, respectively. The Born cross section times the (DD¯∗)∓ branching fraction (σ(e+e−→π±Zc(3885)∓)×Br(Zc(3885)∓→(DD¯∗)∓)) is measured to be (141.6±7.9(stat.)±12.3(syst.)) pb at s√=4.23~GeV and (108.4±6.9(stat.)±8.8(syst.)) pb at s√=4.26~GeV. The polar angular distribution of the π±-Zc(3885)∓ system is consistent with the expectation of a quantum number assignment of JP=1+ for Zc(3885)∓.