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RUI: Hadron Structure and Interactions

RUI：强子结构和相互作用

基本信息

批准号：
2012982
负责人：
Mary Alberg
金额：
$ 19.16万
依托单位：
Seattle University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-15 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2012982&HistoricalAwards=false
关键词：
RUI Hadron Structure Interactions

项目摘要

The determination of proton structure is important for understanding matter in the universe, and a central challenge for theoretical nuclear physics. The proton is constructed from basic building blocks of matter called quarks, antiquarks (antimatter counterparts of the quarks) and gluons, but the ways in which these constituents contribute to the properties of the proton are not completely understood. For example, the proton has a property called spin, which is used in medical applications such as MRI scans, but it is not known how the spins of the quarks and gluons combine to give the spin of the proton. In this project the PI will use new theoretical models of the fluctuation of protons into two-particle states to describe the contributions of quarks and antiquarks created (the proton sea) to the properties of the proton. The results will be compared to experimental measurements from Fermilab, Jefferson Lab, RHIC (the Relativistic Heavy Ion Collider) and other facilities. Undergraduate students will participate in the project, receive training in nuclear and particle physics, and gain experience in research methods and scientific communication. The students will present their work at professional meetings and to the broader public.The scientific goals of this project are: (i) to build a hybrid model for the momentum distributions of the antiquarks in the proton sea by combining a new model for pion-nucleon wave functions, derived by the PI from light-front perturbation theory, with a new statistical model for the momentum distributions of the quarks and antiquarks in the bare proton (no fluctuation) and in the pions and baryons created in the fluctuation states; (ii) to extend this framework to calculate spin distributions in the proton sea by including the contribution of vector mesons to the fluctuations; and (iii) to study the effects of using a new pion-nucleon form factors in calculations of nucleon elastic electromagnetic and axial form factors. The results of the Fermilab SeaQuest experiment will test a hybrid model, and thereby the role of the pion in contributing to the nucleon sea. The extension of the formalism to describe vector meson fluctuations will contribute a new meson cloud model to confront the RHIC experimental measurements of spin asymmetry. The form-factor study will increase the understanding of the role of the pion in pion-nucleon interactions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

质子结构的确定对于理解宇宙中的物质非常重要，也是理论核物理学的核心挑战。质子是由夸克、反夸克（夸克的反物质对应物）和胶子构成的，但这些成分对质子性质的贡献方式还没有完全了解。例如，质子有一种称为自旋的性质，它被用于MRI扫描等医学应用中，但我们不知道夸克和胶子的自旋是如何结合联合收割机来给出质子的自旋的。在这个项目中，PI将使用新的理论模型来描述质子到两粒子状态的波动，以描述夸克和反夸克（质子海）对质子性质的贡献。结果将与费米实验室，杰斐逊实验室，RHIC（相对论重离子对撞机）和其他设施的实验测量进行比较。本科生将参加该项目，接受核物理和粒子物理方面的培训，并获得研究方法和科学交流方面的经验。学生们将在专业会议和更广泛的公众面前展示他们的工作。这个项目的科学目标是：（i）结合PI从光锋微扰理论导出的π-核子波函数新模型，建立质子海反夸克动量分布的混合模型，用一个新的统计模型计算了裸质子中夸克和反夸克的动量分布（无涨落）和在涨落态中产生的π介子和重子;（ii）通过包括矢量介子对涨落的贡献，将这一框架扩展到计算质子海中的自旋分布;研究了在核子弹性电磁和轴向形状因子计算中使用新的π-核子形状因子的影响。费米实验室SeaQuest实验的结果将测试一个混合模型，从而测试π介子在核子海中的作用。扩展到描述矢量介子涨落的形式体系将有助于建立一个新的介子云模型来对抗RHIC自旋不对称性的实验测量。形状因子研究将增加对π介子-核子相互作用中π介子作用的理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。