中文摘要：

采用基于夸克层次的核多体方法研究在超核系统中重子性质的介质修正和超核的性质。采用Friedberg-Lee（FL）模型描述核子和Λ超子,该模型能够给出重子口袋形成的物理机制。重子口袋内的夸克直接与核介质中的标量介子和矢量介子相互作用,因此重子性质在核介质中发生改变。在这一模型中明显考虑了夸克自由度,因此重子性质在核介质中的改变可以在该模型中作详细讨论。该模型可以给出合理的核物质、有限核和Λ超核的结果,同时预言了核介质中重子半径有较大增加。

英文摘要：

Background： The change of hadron properties in nuclear medium is a very active field for both experimental and theoretical research. The study of hypernuclei plays an important role in nuclear physics. Purpose： We aim to study the properties of Lambda hypernuclei and the medium modifications of baryon properties. The quark degrees of freedom are explicitly considered in the model, which enables us to investigate the medium modifications of baryons in a nuclear many-body system and provide a reasonable description of the system in a consistent manner. Methods： We use the Friedberg-Lee （FL） model to describe the nucleon and hyperon in nuclear matter and hypernuclei. The baryon is described as a bound state of three quarks in a nontopological soliton formed by a scalar composite gluon field. The baryons interact through the self-consistent exchange of scalar and vector mesons. The mesons couple directly to the quarks inside the baryons. Results： The properties of baryons are significantly modified in nuclear medium. At normal nuclear matter density, the nucleon radius increases by 13% or so with the parameter Set B, while the Lambda radius increases by 9% or so. The Lambda single-particle energies in hypernuclei are very close to the experimental values. Conclusion： It is shown that the present model is able to provide a reasonable description of Lambda hypernuclei without adjusting parameters, and at the same time it predicts a significant increase of the baryon radius in nuclear medium.