论文标题
该过程的研究$ e^+e^ - \toπ^0π^0 j/ψ$和中性charmonium like状态$ z_c（3900）^0 $
Study of the process $e^+e^-\toπ^0π^0 J/ψ$ and neutral charmonium-like state $Z_c(3900)^0$
论文作者
论文摘要
该过程的横截面$ e^+e^ - \toπ^0π^0 j/ψ$在3.808和4.600 GEV之间的质量中心能量，通过使用12.4 $ fb^{ - 1} $的数据样本，以高精度测量与BESIII检测器一起在BEPCII Collider Collider Colider Facity中收集的数据样本。适合测得的能量依赖性的横截面证实了类似炭的状态$ y（4220）$的存在。 $ y（4220）$的质量和宽度确定为$（4220.4 \ pm2.4 \ pm2.3）$ $ {\ rm mev}/c^{2} $和$（46.2 \ pm4.7 \ pm4.7 \ pm2.1）$ MEV，第一个不遗产是统计和第二个系统的统计。质量和宽度与过程中测量的质量和宽度一致。在$π^0 j/ψ$不变性质量频谱中显着观察到中性炭状状态$ z_c（3900）^0 $，并且首次进行振幅分析以研究其属性。 $ z_c（3900）^0 $的自旋 - 态度确定为$ j^{p} = 1^{+} $，而极点位置为$（3893.1 \ pm2.2 \ pm3.0）-i（22.2 \ pm2.6 \ pm7.0） $ z_c（3900）^\ pm $。此外，提取了$ e^+e^ - \toπ^0 z_c（3900）^0 \toπ^0π^0 j/ψ$的横截面，发现相应的线形与$ y（4220）$的线形一致。
Cross sections of the process $e^+e^-\toπ^0π^0 J/ψ$ at center-of-mass energies between 3.808 and 4.600 GeV are measured with high precision by using 12.4 $fb^{-1}$ of data samples collected with the BESIII detector operating at the BEPCII collider facility. A fit to the measured energy-dependent cross sections confirms the existence of the charmonium-like state $Y(4220)$. The mass and width of the $Y(4220)$ are determined to be $(4220.4\pm2.4\pm2.3)$ ${\rm MeV}/c^{2}$ and $(46.2\pm4.7\pm2.1)$ MeV, respectively, where the first uncertainties are statistical and the second systematic. The mass and width are consistent with those measured in the process $e^+e^-\toπ^+π^- J/ψ$. The neutral charmonium-like state $Z_c(3900)^0$ is observed prominently in the $π^0 J/ψ$ invariant-mass spectrum, and, for the first time, an amplitude analysis is performed to study its properties. The spin-parity of $Z_c(3900)^0$ is determined to be $J^{P}=1^{+}$, and the pole position is $(3893.1\pm2.2\pm3.0)-i(22.2\pm2.6\pm7.0)$ ${\rm MeV}/c^2$, which is consistent with previous studies of electrically charged $Z_c(3900)^\pm$. In addition, cross sections of $e^+e^-\toπ^0 Z_c(3900)^0\to π^0π^0 J/ψ$ are extracted, and the corresponding lineshape is found to agree with that of the $Y(4220)$.
