BESIII上粲偶素跃迁的实验研究

粲偶素各种产生和衰变特性的研究一直是检验和发展标准模型的重要场所，而粲偶素的跃迁过程是研究重夸克偶素产生和衰变特性的重要方法之一，为探索重夸克偶素内部结构及其组分之间的相互作用特点开辟了独特的研究途径，故对粲偶素跃迁特性的实验研究是一个非常重要课题。. 由于以往实验的数据样本太小，粲偶素间的各种跃迁过程从来没有在实验上被系统地研究过，本项研究将利用BESIII直接或间接收集的大量粲偶素样本对粲偶素的跃迁特性进行系统、全面地研究。考虑到BESIII能区微扰QCD理论不太适用，故通过对粲偶素跃迁过程分支比的精确测量和某些已被预言但尚未发现的强跃迁过程的寻找，能够很好的检验QCDME等非微扰QCD理论的有效性，为发展低能QCD理论提供实验依据。

The study of the properties in charmonium production and decay has been playing an important role in examining and developing the Standard Model for a long time. The research for charmonium transitions is one of the key methods to investigate the properties for charmonium production and decay, resulting a special way to reveal the nature and the interaction between the components for charmonium mesons. Thus, experimental study of the properties in charmonium transitions is an important issue.. Charmonium transition has never been systematically studied because of the lack of experimental data. In this project, we will carry out a comprehensive and systematic study for the charmonium transitions based on the huge charmonium data collected at BESIII experiment. Considering the perturbative QCD can not work very well in BESIII energy region, we can well validate the non-perturbative QCD theories, such as QCDME, and develop the low-energy QCD by the precise measurements for the branching fractions of some charmonium transition modes and the searching for the transition processes, which is theoretically long expected but not established experimentally.