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结构（例如质子，中子及其反粒子）及其相互作用有关的两个主题。第一个主题是强子的性质（例如动量和自旋）如何在其组成部分子（夸克，反夸克和胶子）之间分配的基本问题。将使用两个理论框架。在第一种情况下，强子涨落成介子-重子对，强子的部分子分布由涨落中介子和重子的部分子分布决定。在第二章中，我们用统计模型计算了强子的部分子分布。这项研究将解决最近的实验对理论提出的突出挑战之一，质子海中轻夸克分布的动量依赖性。计算还将为费米实验室和JPARC计划的实验提供预测。第二个主题是自旋和奇异性在奇异粒子的产生中是如何联系的基本问题。我们将考虑由一个反质子和一个质子的湮灭产生一个超子及其反粒子（如λ和反λ）的反应。我们的计算将集中在最近的自旋转移测量在欧洲核子研究中心，不同意所有的理论预测。我们还将为GSI/FAIR的PANDA合作计划的实验计算横截面和自旋观测值，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，该大学的学生群体多样化，物理专业的女性比例很高。学生的研究经验将是课程的补充，并提供课堂学习和当代研究的兴奋的整合。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发表论文，海报和演讲。他们还将在由西雅图大学学生研究组织赞助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.