Scattering and Reactions of Intermediate Energy Projectiles

这笔赠款将支持罗格斯大学中能核物理小组的实验工作。罗格斯大学的小组主要在位于弗吉尼亚州纽波特纽斯的托马斯·杰斐逊国家加速器设施的连续电子束加速器CEBAF进行实验。他们的实验旨在提高我们对核子结构的理解。虽然我们知道核子的基本构件是夸克和胶子，但它们如何相互作用使核子具有其观察到的性质仍然不是很清楚。我们的实验使用自旋，这是亚原子粒子的基本性质，作为对核子的灵敏探测器。一种类型的实验测量了极化(自旋排列的)电子从核子散射时所发射的质子的极化。这决定了质子中电荷和磁化强度的分布，以及当质子被束缚在原子核中时，这些分布是如何改变的。另一种类型的实验使用的是氢原子吸收的偏振光子。出射质子的极化对吸收的机制很敏感，因此对夸克和胶子在重离子中相互作用的方式也很敏感。第三种主要类型的实验使用从非极化氦目标散射的电子来研究中子的夸克自旋结构。

This grant will support the experimental work of the Intermediate Energy Nuclear Physics Group at Rutgers University.The Rutgers group carries out experiments primarilyat the continuous electron beam accelerator, CEBAF, located at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. Their experiments are aimed atimproving our understanding of the structure of nucleons. Althoughwe know the basic building blocks of nucleons are quarks and gluons,how they interact to give the nucleon its observed properties isstill not well known. Our experiments use spin, a fundamental propertyof sub-atomic particles, as a sensitive probe of thenucleon. One type of experiment measures the polarization ofejected protons when polarized (spin-aligned) electrons are scatteredfrom nucleons. This determines the distributions of charge andmagnetization in the proton, and how those distributions are changedwhen the proton is bound in a nucleus. Another type of experimentsuses polarized photons absorbed on deuterium. The polarization ofthe outgoing protons is sensitive to the mechanism of the absorption,and hence to the way the quarks and gluons interact in the deuteron. The third major type of experiments use electrons scattered from apolarized helium target to study the quark spin structure of the neutron.