RUI: Studies of Strangeness, Baryon Structure and Exotic Atoms

这个项目将解决当前强相互作用粒子的夸克模型中的问题，以及奇异原子中的一个相关主题。一个问题与质子和反质子碰撞产生的奇怪粒子(西格玛超子和波长超子)及其反粒子有关。我们将在夸克模型中计算这些反应的截面和自旋可观测值，并将它们与实验和介子交换计算进行比较。我们的目标是确定反应机制和未知的超子-反超子相互作用。另一个当代感兴趣的问题是奇怪夸克和反夸克对质子自旋的贡献。我们已经提出了一个质子中极化的本征奇异性模型，我们将进一步发展这个模型，以便用来自超子产生实验的自旋转移数据来测试它。第三个问题是西格玛超子中不同夸克类型(向上、向下和奇怪)的不对称性，我们将在介子与夸克耦合的模型中计算这一点。最后，我们将计算奇异原子的能级位移和宽度，以了解核子波函数和基本强子-核子相互作用。将提供研究助学金，以便本科生可以在这个项目中进行合作。

This project will address current problems in quark models of strongly interacting particles and a related topic in exotic atoms. One problem concerns the production of strange particles (sigma and lambda hyperons) and their antiparticles from collisions of protons and antiprotons. We will calculate in a quark model the cross-sections and spin observables for these reactions, and compare them to experiment and to meson-exchange calculations. Our goal is to determine the reaction mechanism and the unknown hyperon- antihyperon interaction. Another problem of contemporary interest is the contribution of strange quarks and antiquarks to the spin of the proton. We have proposed a model of polarized, intrinsic strangeness in the proton which we will further develop in order to test it against spin transfer data from the hyperon production experiments. A third problem is the asymmetry of different quark flavors (up, down, and strange) in the sigma hyperon, which we will calculate in a model in which mesons are coupled to quarks. Finally, we will calculate energy level shifts and widths in exotic atoms in order to learn about nucleon wave functions and elementary hadron-nucleon interactions. Research assistantships will be provided so that undergraduate students can collaborate in this program.