电子-离子对撞机上开展核子及其激发态研究的建议

Suggestions for the Study of the Nucleon and Nucleon Resonances on the Electron-Ion Collider

核子及其激发态性质研究一直是中高能核物理的一个重要研究领域。然而,到目前为止,对核子及其激发态内部结构的了解还处在初级阶段。首先介绍了核子及其激发态研究现状,指出了三夸克模型在描述核子特别是核子激发态内部结构方面存在很大的缺陷。为解决传统三夸克模型的不足,有一种新的观点认为虽然独立的五夸克态不存在,但是核子及其共振态中存在可观的五夸克激发。这种五夸克图像提供了一个描述核子内部结构的新见解,给出了与经典三夸克图像相当不同的核子激发态谱预言,还有待实验检验。目前国内外正在论证的电子–离子对撞机(EIC)将是研究核子结构下一代最重要的加速器装置,被视为"超级电子显微镜"。由于EIC有较高的能量和亮度,特别是低本底等优势,可以开展核子及其激发态性质的研究以及新强子态研究。

The study of the properties of the nucleon and nucleon resonances is an important field in the high and intermediate energy nuclear physics, however, until now, our understanding about the structure of the nucleon and nucleon resonances is still in its infancy. We give a brief review on the current researches of the nucleon and nucleon resonances, and point out that the classical quark model can not successfully describe the structure of the nucleon and nucleon resonances. For doing this, a new idea claims that although the five-quark state does not exist, but, there could be significant five-quark components in the nucleon and nucleon resonances. This five-quark configure gives different predictions for the nucleon resonances which will be tested by the future experiments. Now, the proposed Electron-Ion Collider (EIC) will be the most important accelerator installation for studying the nucleon structure, and it is called ”super-electronic-microscope”. Because of the high energy and luminosity, and also low background, we can study the properties of the nucleon and nucleon resonances and new hadron states on EIC.