Precision Measurements of Fundamental Symmetries and SIDIS

这项拨款支持研究，以完成质子的弱电荷的测定，并研究基本物质和相互作用的标准模型的新方面。标准模型以一种优雅的方式描述了四种自然力中的三种；这三种力分别是电磁相互作用，弱相互作用和强相互作用。质子的弱电荷是一种基本性质，就像它的电荷和质量一样，它决定了质子对弱相互作用的反应。它还与弱相互作用和电磁相互作用如何相互混合有关。因为标准模型预测了混合如何随着相互作用中交换的动量量而变化，所以在低动量转移值下对质子弱电荷的精确测量是对标准模型的严格测试。此外，它对标准模型中尚未包含的物理特性很敏感。该奖项的研究项目还包括测量半包容深度非弹性散射，这种散射对夸克水平上的电荷对称破缺很敏感，并进一步扩展了我们对基本相互作用的理解。这项拨款支持的研究小组将重新委托杰斐逊实验室的莫特偏振计。该偏振计将测量杰弗逊实验室电子束中电子自旋的排列；他们知道，排列对于向实验室的四个实验大厅提供极化电子束是至关重要的。硬件和软件问题都将在这个项目中得到解决，因此学生和博士后研究人员将获得广泛的有价值的技能。这些对杰斐逊实验室两极分化项目和年轻科学家培训的广泛影响交织在研究项目中。

This grant supports research to complete the determination of the weak charge of the proton and investigate new aspects of the Standard Model of fundamental matter and interactions. The Standard Model describes three of the four forces of nature in an elegant manner; those three forces are the electromagnetic interaction, the weak interaction, and the strong interaction. The weak charge of the proton is a basic property, like its electric charge and mass, which determines the proton's response to the weak interaction. It is also related to how the weak and electromagnetic interactions mix with each other. Because the Standard Model predicts how that mixing varies with the amount of momentum that is exchanged in an interaction, a precise measurement of the proton's weak charge at a low value of momentum transfer is a rigorous test of the Standard Model. Additionally, it is sensitive to physics not yet included in the Standard Model. The research program of this award also includes measurements of semi-inclusive deep inelastic scattering that is sensitive to charge symmetry breaking at the quark level and further extends our understanding offundamental interactions.The research group supported by this grant will re-commission the Mott polarimeter at Jefferson Lab. That polarimeter will measure the alignment of electron spins in the electron beam of Jefferson Lab; knowing that alignment is crucial to providing polarized electron beams to the four experimental halls of the Lab. Both hardware and software issues will be addressed in this project so the student and postdoctoral researchers will gain a wide range of valuable skills. These broader impacts on the polarized program of Jefferson Lab and the training of young scientists are interwoven into the research program.