RUI: Hadron Structure and Interactions

质子是一种粒子，它对我们理解宇宙中的物质至关重要。它存在于每个原子的原子核中，并有助于聚变反应，为恒星提供燃料。质子是由夸克、反夸克（与夸克对应的反物质）和胶子等基本物质构成的，但这些成分对质子性质的贡献方式尚不完全清楚。例如，质子有一种叫做自旋的特性，它被用于医学上的应用，比如核磁共振成像扫描，但是关于夸克和胶子的自旋是如何结合起来产生质子自旋的详细知识仍然是未知的。在这个项目中，研究者将使用理论模型来研究奇异夸克和反夸克对质子性质的贡献，并将结果与费米国家加速器实验室和杰斐逊国家加速器设施等设施的实验测量结果进行比较。本科生将参与该项目，接受核与粒子物理方面的培训，这是对他们本科课程的补充，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作品。这个项目的目标是确定质子的奇异度分布和奇异度对质子电磁特性的贡献。质子的奇异性是指它的奇异夸克和反奇异夸克，它们是由质子进入介子-重子状态的波动或夸克和胶子的相互作用产生的。奇异分布描述了由奇异夸克或反奇异夸克携带的质子动量份额，它们可能彼此不同（奇异不对称）。奇异度分布对我们理解质子的结构很重要，因为它们会影响暗物质搜索预测的横截面。PI和她的学生将开发一个介子云模型，以表示质子进入奇异介子和奇异重子对的波动。一个统计模型将被用来描述介子和重子中由夸克和胶子相互作用产生的奇怪分布。将与完全陌生性和陌生性不对称的实验结果进行比较。奇异性波函数的光锥模型将用于计算奇异性电和磁形状因子，由此可以从实验测量中确定核子的奇异性限制。

The proton is a particle that is central to our understanding of matter in the universe. It is found in the nucleus of every atom and contributes to the fusion reactions that fuel the stars. Protons are constructed from basic building blocks of matter called quarks, antiquarks (the 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 detailed knowledge of how the spins of the quarks and gluons combine to give the spin of the proton is still missing. In this project the investigator will use theoretical models to study the contributions of strange quarks and antiquarks to the properties of the proton and compare the results to experimental measurements from facilities such as the Fermi National Accelerator Laboratory and the Jefferson National Accelerator Facility. Undergraduate students will participate in the project, receive training in nuclear and particle physics that is complementary to their undergraduate coursework and gain experience in research methods and scientific communication. The students will present their work at professional meetings and to the broader public. The goal of this project is to determine the strangeness distributions of the proton and the contribution of strangeness to the proton's electromagnetic properties. Strangeness in the proton refers to its strange and anti-strange quarks, which are created by fluctuations of the proton into meson-baryon states or by quark and gluon interactions. Strangeness distributions describe the share of the proton's momentum that is carried by the strange or anti-strange quarks, which may differ from one another (strangeness asymmetry). Strangeness distributions are important both for our understanding of the structure of the proton, and because they affect the cross sections predicted for dark matter searches. The PI and her students will develop a meson cloud model to represent the fluctuations of the proton into pairs of strange mesons and strange baryons. A statistical model will be used to describe the strange distributions that are created in the mesons and baryons by quark and gluon interactions. Comparison will be made with experimental results for total strangeness and strangeness asymmetry. A light cone model of strangeness wave functions will be used to calculate strangeness electric and magnetic form factors, from which limits on strangeness in the nucleon can be determined from experimental measurements.