Probing Nucleon Structure and the Nucleon-Nucleon Force

我们研究的总体目标是从夸克和胶子的角度研究核子的结构和核子的共振。夸克和胶子之间的基本相互作用是量子色动力学(QCD)理论，它被普遍认为是强力的正确基础理论。然而，在接近核子质量的能量下，使用QCD进行实际计算是非常困难的。因此，需要实验数据来指导核子结构的理论模型。此外，我们对两个核子之间强相互作用中电荷对称性的实验测试感兴趣。我们的研究集中在托马斯·杰斐逊国家加速器设施(TJNAF)和布鲁克海文国家实验室的激光电子伽马源(LEGS)的实验工作。这两个设备都提供了足够能量的电子束或光子束，以激发核子进入中间共振，然后衰变。在TJNAF的B厅，我们小组专注于测量介子，这在很大程度上是由于各种核子共振的衰减。在TJNAF的C厅，我们小组的一名成员正在测量中子的电磁形状因数。在LEGS，我们团队的两名成员正在对由极化光束和目标产生的介子进行测量，这将测试理论求和规则(与核子的静态性质有关)。这三个实验都将为QCD激发的理论工作提供指导。

0072226HicksThe general goal of our research is to study the structure of the nucleon and the nucleon resonances in terms of quarks and gluons. The fundamental interaction between quarks and gluons is the theory of quantum chromodynamics (QCD), which is generally accepted to be the correct underlying theory of the strong force. However, practical calculations using QCD are extremely difficult at energies near the mass of the nucleon. Hence, experimental data is needed to guide theoretical models of nucleon structure. In addition, we are interested in experimental tests of charge symmetry in the strong interaction between two nucleons.Our research is centered on experimental work at the Thomas Jefferson National Accelerator Facility (TJNAF) and the Laser-Electron Gamma Source (LEGS) at Brookhaven National Laboratory. Both of these facilities provide electron or photon beams of sufficient energy to excite the nucleon into intermediate resonances which then decay. In Hall B at TJNAF, our group is focussed on measurements of kaons which are largely due to decay of various nucleon resonances. In Hall C at TJNAF, one member of our group is working on a measurement of the electric and magnetic form factor of the neutron. At LEGS, two members of our group are working on measurements of pions produced with polarized beams and targets, which test theoretical sum rules (related to static properties of the nucleon). All three experiments will provide guidance to QCD-inspired theoretical work.