Observation of a Neutral Structure near the $D\bar{D}^{*}$ Mass Threshold in $e^{+}e^{-}\to (D \bar{D}^*)^0π^0$ at $\sqrt{s}$ = 4.226 and 4.257 GeV
hep-ex
/ Authors
BESIII Collaboration, M. Ablikim, M. N. Achasov, X. C. Ai, O. Albayrak, M. Albrecht, D. J. Ambrose, A. Amoroso, F. F. An, Q. An
and 395 more authors
J. Z. Bai, R. Baldini Ferroli, Y. Ban, D. W. Bennett, J. V. Bennett, M. Bertani, D. Bettoni, J. M. Bian, F. Bianchi, E. Boger, I. Boyko, R. A. Briere, H. Cai, X. Cai, O. Cakir, A. Calcaterra, G. F. Cao, S. A. Cetin, J. F. Chang, G. Chelkov, G. Chen, H. S. Chen, H. Y. Chen, J. C. Chen
/ Abstract
A neutral structure in the $D\bar{D}^{*}$ system around the $D\bar{D}^{*}$ mass threshold is observed with a statistical significance greater than 10$σ$ in the processes $e^{+}e^{-}\rightarrow D^{+}D^{*-}π^{0}+c.c.$ and $e^{+}e^{-}\rightarrow D^{0}\bar{D}^{*0}π^{0}+c.c.$ at $\sqrt{s}$ = 4.226 and 4.257 GeV in the BESIII experiment. The structure is denoted as $Z_{c}(3885)^{0}$. Assuming the presence of a resonance, its pole mass and width are determined to be ($3885.7^{+4.3}_{-5.7}$(stat)$\pm 8.4$(syst)) MeV/$c^{2}$ and ($35^{+11}_{-12}$(stat)$ \pm 15$(syst)) MeV, respectively. The Born cross sections are measured to be $σ(e^{+}e^{-}\to Z_{c}(3885)^{0}π^{0}, Z_{c}(3885)^{0} \to D\bar{D}^{*})=(77 \pm 13$(stat)$\pm 17$(syst)) pb at 4.226 GeV and ($47 \pm 9$(stat)$ \pm 10$(syst)) pb at 4.257 GeV. The ratio of decay rates $\frac{\mathcal{B}({Z_{c}(3885)^{0} \to D^{+}D^{*-}+c.c.})}{\mathcal{B}({Z_{c}(3885)^{0} \to D^{0}\bar{D}^{*0}+c.c.})}$ is determined to be $0.96 \pm 0.18$(stat)$\pm 0.12$(syst), consistent with no isospin violation in the process $Z_{c}(3885)^{0}\to D\bar{D}^*$.