RUI: Models of Hadron Structure and Interactions

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。在这个项目中，我们研究了理论核物理中与强子（如质子、中子和它们的反粒子）的结构和它们的相互作用有关的两个主题。第一个主题是关于强子的性质（例如动量和自旋）如何在其组成部分：夸克、反夸克和胶子之间分布的基本问题。将使用两个理论框架。在第一种方法中，强子波动成介子-重子对，强子的部分子分布由波动中的介子和重子的部分子分布决定。其次，在统计模型中计算了强子的部分子分布。本研究将解决最近实验对理论提出的一个突出挑战，即质子海中轻夸克分布的动量依赖性。这些计算还将为费米实验室和日本研究中心计划进行的实验提供预测。第二个主题是关于自旋和奇异性在奇异粒子产生中的关系的基本问题。我们将考虑由反质子和质子湮灭产生超子及其反粒子（例如λ和反λ）的反应。我们的计算将集中在欧洲核子研究中心最近的自旋转移测量上，这些测量与所有理论预测都不一致。我们还将为GSI/FAIR的PANDA合作计划的实验计算截面和自旋观测值，这将把CERN的测量扩展到更高的能量。这项工作将与来自西雅图大学的本科生研究助理一起进行，西雅图大学的学生群体多样化，女性物理专业的比例很高。学生的研究经验将是对课程作业的补充，并提供课堂学习和当代研究兴奋的整合。学生将接受研究方法和科学交流方面的培训。他们将在团队中工作，指导年轻的学生，并在专业协会的会议上以论文、海报和演讲的形式展示他们的工作。他们还将在西雅图大学学生研究组织主办的研讨会和活动中与当地校园社区分享他们的工作。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).In this project we study two topics in theoretical nuclear physics related to the structure of hadrons (e.g. protons, neutrons and their antiparticles) and to their interactions. The first topic is the fundamental question of how the properties of a hadron (e.g. momentum and spin) are distributed among its constituent partons: quarks, antiquarks and gluons. Two theoretical frameworks will be used. In the first, a hadron fluctuates into meson-baryon pairs, and the hadron's parton distribution is determined by the parton distributions of the mesons and baryons in the fluctuations. In the second, the hadron's parton distributions are calculated in a statistical model. This study will address one of the outstanding challenges to theory posed by recent experiment, the momentum-dependence of light quark distributions in the proton sea. The calculations will also provide predictions for experiments planned at Fermilab and JPARC. The second topic is the fundamental question of how spin and strangeness are related in the production of strange particles. We will consider reactions in which a hyperon and its antiparticle (e.g. Lambda and anti-Lambda) are created by the annihilation of an antiproton and a proton. Our calculations will focus on recent spin transfer measurements at CERN, which disagree with all theoretical predictions. We will also calculate cross sections and spin observables for the experiments planned by the PANDA collaboration at GSI/FAIR, which will extend the CERN measurements to higher energies. This work will be carried out with undergraduate research assistants from Seattle University, which has a diverse student population and a high percentage of women physics majors. The student research experience will be complementary to coursework, and provide an integration of classroom learning and the excitement of contemporary research. Students will receive training in research methods and scientific communication. They will work in teams, mentor younger students and present their work in papers, posters and talks at meetings of professional societies. They will also share their work with the local campus community in seminars and events sponsored by Seattle University student research organizations.