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。 这个小组主要在弗吉尼亚州纽波特纽斯的杰斐逊实验室的新的连续电子束加速器CEBAF上进行电子束实验。 他们是为该设施设计和建造大型偏振计的领导者;它确定了被高能电子从原子核中撞出的质子的自旋方向。 用这种偏振计进行测量，可以获得关于自由质子基本电磁特性的高度精确的信息，并可以揭示质子被束缚在原子核内时这些特性可能发生的变化。 相关实验将在德国美因茨的一个加速器上以较低的能量进行。 其他这样的自旋测量将测试简单的夸克模型描述的反应，其中质子从氘靶发射的入射高能光子。 自旋测量比以前的实验更敏感的夸克描述的反应中可能存在的问题。 最后，第三个主要程序直接讨论了夸克对中子自旋的贡献，方法是当中子在靶中的自旋方向改变时，检查散射电子的概率的变化。

This grant will support the experimental work of the Intermediate Energy Nuclear Physics Group at Rutgers University. This group carries out experiments with electron beams primarily at the new continuous electron beam accelerator, CEBAF, at the Jefferson Laboratory in Newport News, Virginia. They were leaders in designing and constructing a large polarimeter for this facility; it determines the direction of the spin of protons knocked out of the nucleus by the highly energetic electrons. Measurements with this polarimeter yield highly accurate information on the fundamental electromagnetic properties of the free proton, and should reveal possible changes in these properties when the proton is bound inside a nucleus. Related experiments will be carried out at lower energies at an accelerator in Mainz, Germany. Other such spin measurements will test simple quark model descriptions of reactions in which protons are emitted from a deuterium target by incident high-energy photons. The spin measurements are much more sensitive than previous experiments to possible problems in the quark description of the reaction. Finally, a third major program addresses directly the contributions of quarks to the spin of the neutron by examining changes in the probability for scattering electrons when the direction of the neutron's spin in the target is changed.