Theoretical Study of Nucleon Structure and Hadronic Interactions

核子结构与强子相互作用的理论研究

• 批准号: 1205019
• 负责人: John Londergan
• 金额: $ 27万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-15 至 2016-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1205019&HistoricalAwards=false
• 关键词: Theoretical; Study; Nucleon; Structure; Hadronic

Neutrons and protons, the constituents of the atomic nucleus, are composed of quarks. We study the quark substructure of nucleons and also particles that contain heavy quarks. We focus on approximate symmetries of quarks such as flavor symmetry and charge symmetry, which would be an exact symmetry if protons and neutrons were identical. We plan to study high-energy nuclear reactions that produce heavy quarks, where we can differentiate between "extrinsic" quarks produced by gluon splitting and "intrinsic" heavy quarks such as appear in meson-cloud models. We will particularly focus on possibilities for observing heavy-quark production at a future electron-ion collider. We will continue our investigations of the effects of Regge exchange on hard exclusive processes. Amplitudes that include Regge exchange violate the factorization theorem for hard exclusive processes and thus acquire a measurable dependence on the four-momentum transfer. We will carry out simulations of electrons or atoms moving in small two-dimensional nanoscale systems, where the wave nature of particles produces large effects. This work involves training of undergraduates and postdocs, who become experts in complex systems with application to technology, defense, communications and finance. Recent postdocs have included several women. The principal investigator gives seminars on advances in physics for non-scientists, increasing scientific literacy in the general population. The PI is recently participating in a "Big History" collaboration involving physicists, astronomers, geologists, biologists and anthropologists. This collaboration has produced two symposia, a museum exhibit and a Web site, with plans to produce DVDs and a book in the future.

组成原子核的中子和质子是由夸克组成的。我们研究了核子和含有重夸克的粒子的夸克子结构。我们着重于夸克的近似对称性，如风味对称和电荷对称，如果质子和中子相同，这将是一种精确对称。我们计划研究产生重夸克的高能核反应，在那里我们可以区分由胶子分裂产生的“外在”夸克和出现在介子云模型中的“内在”重夸克。我们将特别关注在未来的电子-离子对撞机上观察重夸克产生的可能性。我们将继续调查Regge交换对硬独占进程的影响。包含Regge交换的振幅违反了硬排他过程的因式分解定理，因此获得了对四动量转移的可测量依赖。我们将模拟电子或原子在小型二维纳米级系统中的运动，其中粒子的波动性质产生了很大的影响。这项工作包括培养本科生和博士后，使他们成为应用于技术、国防、通信和金融等复杂系统的专家。最近的博士后中有几名女性。首席研究员为非科学家举办关于物理学进展的研讨会，提高普通大众的科学素养。PI最近参与了一个由物理学家、天文学家、地质学家、生物学家和人类学家参与的“大历史”合作项目。这次合作已经举办了两次专题讨论会、一次博物馆展览和一个网站，并计划在未来制作dvd和一本书。