粲偶素衰变J/psi->Lambda Sigma pi中重子激发态分波分析与新重子寻找

Study of baryon spectrum could be important for us to understand the quark gluon structure in baryons. There exist some puzzles like "missing baryons"、“mass inverse”in classical Quark Model, both experimental and theoretical study show us the possibility to study the inertial effective dynamical degree of freedom in baryons. There exists some problems in conventional scattering experiments, i.e.: weak coupling between photon and nucleons, et al. So charmonium decay provide a new platform to study baryons. A series of progress with BES experiment has been made from 2000, 3 new excited nucleons have been observed at BES. With the world largest J/psi sample collected at Beijing Spectrometer, we planned to study exited baryons （Sigma(1385),Lambda(1520),Lambda(1405)et al.）and search two new baryons with spin -parity 1/2- from expectation.

重子谱的研究，有助于理解重子内部的夸克胶子结构。夸克模型在解释激发态重子谱时遇到了如“丢失的重子”、“质量反置”等困难，实验与理论研究表明我们需要进一步了解重子内部的有效动力学自由度。传统散射实验研究存在着如光子与核子耦合较弱等问题，通过粲偶素衰变到重子末态来研究重子谱则提供了一个新的方向。北京谱仪实验自2000年来在重子谱特别是核子谱方面取得了一系列重要物理进展，发现了3个粒子数据表上以前并未列出的核子态。利用北京谱仪获得的世界上最大统计量的J/psi事例样本，我们拟通过J/psi->Lambda Sigma pi 衰变研究重子激发态（Sigma(1385),Lambda(1520),Lambda(1405),并对理论预言的两个自旋、宇称为1/2-的新重子（Sigma(1380),Lambda(1570)）进行寻找与研究。。