Lambda*和Xi*的寻找及研究

重子激发态的研究是国际粒子物理与核物理前沿的重要组成部分。对重子及其激发态的研究，对于理解物质的基本结构、检验和发展各种理论模型都有重要的意义。通过J/psi和psi(3686)衰变研究重子激发态为粒子物理研究开辟了一个新的领域，J/psi和psi(3686)衰变的同位旋约束、实验分析方法的进步等使得该项工作比以往的散射实验具有明显的优势。BESIII已经取得大约100亿J/psi数据和4.5亿psi(3686)数据,分波分析方法也通过多次物理分析工作的发展和检验，趋于成熟和完善。我们期待通过对BESIII实验数据的分波分析进一步确认BESII上发现的新重子激发态Lambda(1570)、测量和确认Xi*的自旋-宇称以及质量宽度等参数、研究KLambda的近阈增强结构Nx(1625)和寻找其他“丢失”的重子激发态等。

Study of excited baryons plays an important role in the frontier of particle and nuclear physics, which is important for understanding on the basic structure of matters, testing and development of theoretical models. Using J/psi and psi(3680) decays, the study of excited baryons is a new field of particle physics. This research has obvious advantages comparing to the previous scattering experiment due to the constraint of isospin in J/psi decays, and the improvement of experimental analysis method etc. The BESIII experiment has already collected about 10000M J/psi and 450M psi(3680) data, and the partial wave analysis has been improved and matured after being used for many physics analyses. Based on the partial wave analysis with BESIII data, we expect to confirm the new excited baryon state such as Lambda(1570), which was firstly observed at BESII. We will measure and confirm the spin-parity and masses and widths of Xi* states and study the near-threshold enhancement of KLambda mass spectrum,Nx(1625), as well as search for the "missing" excited baryon states.