Confirmation of a charged charmoniumlike state Zc (3885)? in e+e- ??± (D D ¯ ?)? with double D tag

Abstract

We present a study of the process e+e-??±(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 ?± 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-??+D0D?- and e+e-??+D-D?0. By performing a simultaneous fit, the statistical significance of Zc(3885)? signal is determined to be greater than 10?, and its pole mass and width are measured to be Mpole=(3881.7±1.6(stat)±1.6(syst)) MeV/c2 and ?pole=(26.6±2.0(stat)±2.1(syst)) MeV, respectively. The Born cross section times the (DD¯?)? branching fraction (?(e+e-??±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 ?±-Zc(3885)? system is consistent with the expectation of a quantum number assignment of JP=1+ for Zc(3885)?. © 2015 American Physical Society.