BESIII实验上e+ e- ->D Dbar (π) π产生的研究

The study of charmonium spectrum is a hot topic in the frontier of hadron physics. Above DDbar mass threshold, ψ(4415) is one of higher excited charmonia, which is discovered by the experiment of e+e- annihilation. At present, its property is not well understood. There are some contradictions between different theoretical explanations for ψ(4415), and the evidence of the experiment is limited for the study of ψ(4415). In the project, we will focus on a deep understanding of the high excited charmonium ψ(4415) related Physics. Based on the BESIII data samples with high luminosity around 4.4 GeV, the processes e+e- ->DD_1 ->DDbarππ and e+e- ->DD_2->DDbarπ will be studied to improve our knowledge on the property of ψ(4415) and the hadronic decays of the vector charmonium. Meanwhile, we will search the possible bound states of D-Dbar system near D-Dbar threshold in the process e+e- ->D+D-π+π-.

粲夸克偶素谱的研究一直是强子物理前沿的热点问题。在粲介子对产生质量阈值之上， ψ(4415)是实验上已经发现的一个高激发态的粲夸克偶素态。目前对它的性质了解得还不够充分，不同理论的解释也存在争议，而ψ(4415)的实验研究也很有限。本项目旨在深入理解高激发态的粲夸克偶素ψ(4415)相关物理的研究。基于BESIII实验上质心系能量4 GeV以上的高统计量数据，本项目通过对e+e- ->DD_1 ->DDbarππ和e+e- ->DD_2->DDbarπ过程的研究，将提升我们对矢量粲夸克偶素介子ψ(4415)的性质及其强衰变的了解。同时，我们还将在e+e- ->D+D-π+π-过程中寻找可能的D-Dbar束缚态。

粲夸克偶素物理的研究一直是高能物理前沿的热点问题。在粲介子对产生质量阈值之上，粲夸克偶素高激发态ψ(4415)的性质还不太了解。不同理论对ψ(4415)的解释存在争议，而ψ(4415)的实验研究也很有限。本项目基于BESIII实验在4.340-4.600 GeV采集的大统计量数据研究了e^+e^- -> DD_1 -> D^+D^-π^+π^-过程和e^+e^- -> DD_2 -> D^0D^-π^+过程，探讨了可能存在的中间共振态ψ(4415)，并测量了相应过程的玻恩截面。.此外，我们还用BESIII实验采集的4.5亿ψ(3686)数据样本研究了χ_cJ (J=0,1,2)电磁辐射衰变到矢量介子(ρ,ω,φ)过程，首次观测到了信号显著度超过5倍标准偏差的χ_c2 -> γρ^0过程，为理解粲偶素P波三重态χ_cJ电磁跃迁到矢量介子的性质提供了坚实的实验证据。