Hadronic and Nuclear Structure and Dynamics

这个项目的目标是通过广泛应用和发展基于有效理论概念的方法来促进对强子和轻核的理论理解。这些有效的理论允许描述强子和核系统，保持了与强相互作用的基本理论--量子色动力学(QCD)的严格联系。其中一项研究将通过被称为QCD的1/N展开的理论框架来解决激发重子的现象学问题，其中N是颜色自由度的数量。这一计划与目前杰斐逊实验室和其他地方关于激发重子的实验计划有关。我们还将对1/N展开的一些基本方面进行理论研究，特别是对QCD中手征对称性的自发破缺现象进行研究。另一项研究将解决用有效的理论描述低能和中能QCD的问题。特别是，该项目将考虑通过将激发介子态包含在有效理论中来将QCD的低能有效理论(手征微扰理论)的有效范围扩展到中能域的问题。有效理论在核物理中的应用将集中在研究核电流矩阵元素的低能展开，特别是电磁电流，对于这种低能展开，可能有大量的唯象应用。该项目还有一个重要的教育部分，其中包括培训一名博士生和与博士后同事合作。

The goals of this project are to advance the theoretical understanding of hadrons and light nuclei through the application and development of methods broadly based on the concept of effective theories. These effective theories allow for a description of hadronic and nuclear systems preserving a rigorous connection with the fundamental theory of the strong interactions, Quantum Chromodynamics (QCD). One of these studies will address the phenomenology of excited baryons by means of a theoretical framework known as the 1/N expansion of QCD, where N is the number of color degrees of freedom. This plan is of relevance to the current experimental programs on excited baryons at Jefferson Lab and elsewhere. Theoretical studies of some fundamental aspects of the 1/N expansion will also be carried out, especially with focus on the phenomenon of spontaneous breaking of the chiral symmetry in QCD. Another study will address the problem of describing QCD at low and intermediate energies with effective theories. In particular, the project will consider the problem of extending the range of validity of the low energy effective theory of QCD known as Chiral Perturbation Theory to the intermediate energy domain through the inclusion of excited meson states in the effective theory. The application of effective theories to nuclear physics will focus on the study of the low energy expansion of nuclear current matrix elements, in particular electromagnetic currents, for which a large number of phenomenological applications are possible. The project has also an important education component, which includes the training of a PhD student and collaborations with postdoctoral associates.