在diquark图像下研究qqQ重子质量谱、强衰变及混合问题

The mass spectrum, strong decay and the mixing questions of the qqQ (q=u/d quark,Q=c/b quark) baryons are the hot issues in the hadron physics. However, they were usually studied independently in the previous literature. The relations of them were rarely researched yet.In this program, we will explore the property of the excited qqQ baryons systematically in the "diquark" picture. The constituent-quark potential model, the 3P0 strong decay model, the heavy-quark effective theory and the angular momentum theory will be synthetically considered in this work. Firstly, the mixing questions of qqQ baryons will be investigated and the mass spectrum will be presented in the quark potential model. Secondly,the decay widths and some important branching fractions will be given with the help of the 3P0 strong decay model. There the mixing effect will be considered.Lastly, the analysis of the channel coupling effect which may be important for both mass and decay width will be completed. All results will be presented in a relatively uniform picture and can be tested in future experiments.Therefore, the role of heavy-quark symmetry which plays in the strong decays of qqQ baryons will be checked and the validity of "diquark" in qqQ baryons will be clarified further.All results shown in this project could help us to understand the dynamics of baryons better.

qqQ重子（q=u,d夸克,Q=c,b夸克）的质量谱、强衰变及混合问题一直是强子物理中的热点问题。但以往的文献大多将它们作为独立的问题单独研究，较少考虑它们之间的联系。本项目在diquark的物理图像下,将qqQ型重子作为准两体系统，结合组份夸克势模型、 3P0强衰变模型、重夸克有效理论及角动量理论，系统地研究qqQ重子激发态的性质。首先，我们将利用组份夸克势模型给出qqQ重子的质量谱，并讨论混合问题；其次，结合3P0强衰变模型，系统计算出qqQ激发态的衰变宽度以及重要的分支比值（考虑混合效应）；最后，我们将讨论耦合道效应对这类重子质量谱和强衰变的影响。所有的结果将在一个相对完整的物理图像下给出，由今后的实验来检验。这些结果可以帮助检验重夸克对称性在qqQ型重子的强衰变中所起的重要作用，以及"diquark"物理图像在这类重子中存在的假设是否合理，为我们进一步理解重子的动力学提供帮助。

过去的三年，我们按照申请书设定的科学目标展开了相关研究工作。首先，我们对2S和1D波的1^-和3^-态的粲、粲奇异介子展开深入研究，给出了实验上发现的相关态的量子态安排，并发现Eichten-Hill-Quigg（EHQ）公式适合研究重-轻体系的强衰变。据此，将该方法推广到要研究的重味重子系统。其次，在相对论流管模型下，体统研究了相关的粲、底重子的能谱，并提取了diquark的质量。再次，在diquark图像下，借助于非相对论组份夸克模型，系统计算了具有低激发能的粲重子质量谱和衰变宽度。另外，我们也开展对底重子的计算。其它的工作还包括详细探讨X(1872)和\eta_2(1870)的性质，以及利用Regge唯象计算双重夸克和三重夸克重子的能谱。