Zc(3900)与粲介子的耦合的寻找

Search for the Coupling of Z_c(3900) and Charm Meson

继发现带电类粲偶素结构Zc(3900)之后,北京谱仪(BES Ⅲ)又发现了一系列带电的和中性的Zc粒子.为了理解这些Zc粒子的内部结构和性质,BESⅢ实验利用其在质心系能量4.23和4.26 GeV处采集的数据样本对e^+e^-→π~±(DDˉ*)?和e+e-→π~0(DD~*)~0过程进行了研究.在DD~*系统中分别观测到1个带电的类粲偶素结构Zc(3885)~?和1个中性的类粲偶素结构Zc(3885)0,且他们的极点质量和宽度在1σ范围内一致,因此Z_c(3885)极有可能是1个类粲偶素同位旋3重态.BESⅢ实验还测量了π±Z_c(3885)~?系统的角分布,结果显示其带电Zc(3885)?的自旋宇称量子数JP符合1+的预期.

Since the observation of the charmonium-like state Z_c（3900）, BES Ⅲ experiment has observed a series of Zcparticles. To understand the structure and the nature of these particles, both e＋e-→ π±（DDˉ＊）？and e＋e-→ π~0（DD~＊）~0 were investigated by using data samples collected with the BES Ⅲ detector. The charged and neutral charmonium-like states, called Z_c（3885）~？ and Z_c（3885）~0 respectively, were observed in the DD~＊ invariant mass distribution. Their pole mass and width are close to each other within 1σ, so Zc（3885） is possibly an isospin triplet of a charmonium-like state. The measured angular distribution of the charged π±Zc（3885）~？ system favors the expectation for a JP=1~＋ quantum number assignment for the Z_c（3885）.