Theoretical Studies of Hadronic and Nuclear Dynamics

我们的研究重点是研究核强子动力学，特别强调它与夸克和胶子的基本理论量子色动力学（QCD）的关系。特别感兴趣的是研究手征对称性的作用，这是QCD的基本对称性之一。称为手征微扰论的有效场论提供了一个系统和实用的框架，将QCD的对称性转化为实际构成原子核的强子的对称性。拟议的研究广泛使用这种形式主义。为了描述那些目前超出手征微扰理论适用范围的现象，使用了近似反映QCD对称性并可应用于复杂核的模型。具体地说，我们建议研究：核手征微扰理论在少核子体系中的应用，少核子体系中弱过程辐射修正的有效场论估计和μ-氘俘获反应和中微子-氘反应的现有理论处理的系统改进，核手征微扰理论在高能动量转移非弹性反应中的应用，以及核手征微扰理论在高能动量转移非弹性反应中的应用。以及中微子-氘反应超过π介子产生阈值。有效场论的方法是非常有用的，在我们试图将原子核的性质与夸克和胶子的基本动力学联系起来。我们的研究不仅加深了对核-强子物理的理解，而且对核天体物理和寻找标准模型之外的物理也有重要意义。我们的研究与正在进行和未来的中微子实验有着特别密切的联系，这些实验旨在寻找非标准物理学的信号。预算允许我们聘请一名博士后研究员和一名本科生加入我们的研究工作。

The focus of our research is to investigate nuclear-hadronic dynamics with a particular emphasis on its relation to quantum chromodynamics (QCD), the fundamental theory of quarks and gluons. Of particular interest is studying the role of chiral symmetry, which is one of the basic symmetries of QCD. The effective field theory named chiral perturbation theory offers a systematic and practical framework to translate the symmetries of QCD into those of hadrons, particles that actually constitute atomic nuclei. The proposed research makes extensive use of this formalism. To describe those phenomena that are at present beyond the applicability of chiral perturbation theory, models are used that approximately reflect the symmetries of QCD and that can be applied to complex nuclei. Specifically, it is proposed to study: eonsequences of nuclear chiral perturbation theory as applied to few-nucleon systems; effective-field-theoretical estimation of radiative corrections for weak processes in few-nucleon systems and systematic improvements of the existing theoretical treatments of the muon-deuteron capture reaction and neutrino-deuteron reactions; nuclear chiral perturbation theory applied to inelastic reactions involving rather high energy-momentum transfers; and neutrino-deuteron reactions beyond the pion-production threshold. The effective field theory approach is known to be highly useful in our attempt to relate the properties of atomic nuclei to the underlying dynamics of the quarks and gluons. Our investigations not only deepen the understanding of nuclear-hadron physics but also have important bearing upon nuclear astrophysics and search for physics beyond the standard model. Our study has particularly close connections with the on-going and future neutrino experiments that are meant to look for signals for non-standard physics. The budget allows us to hire a post-doctoral fellow and an undergraduate student to join our research effort.