Probing the Standard Model with Parity-Violating Electron Scattering

这笔拨款支持试图回答关于物质的一个基本问题的研究。弱电物理的标准模型没有描述的任何新物理的本质是什么？这个问题将由托马斯·杰斐逊国家加速器设施(TJNAF)的量子弱实验来解决。它将在极低的动量转移下通过破坏宇称的电子散射来测量质子的中性弱电荷。质子的弱电荷在标准模型中有一个明确的预测；对它的精确测量对许多扩展标准模型的流行场景很敏感。我们小组为实验建造并安装了三个硬件系统-一组水平漂移室，一组光度监测器，以及光晕和低束电流监测探测器。在这项资助期间，我们将在数据采集期间维护我们的硬件系统，分析数据，并提取物理结果。我们还将开始进行一项新批准的TJNAF实验，以测试标准模型--Moller实验--这是一种精确测量极化电子与未极化电子弹性散射中违反宇称的不对称性的方法。我们正在进行的项目涉及广泛的硬件和软件任务，这些任务将有助于该项目的研究生和本科生的教育。

This grant supports research that seeks to answer a fundamental question about matter. What is the nature of any new physics not described by the Standard Model of electroweak physics? This question will be addressed by the Qweak experiment at the Thomas Jefferson National Accelerator Facility (TJNAF). It will measure the proton's neutral weak charge via parity-violating electron scattering at very low momentum transfer. The proton's weak charge has a well-defined prediction in the Standard Model; a precise measurement of it is sensitive to many popular scenarios for extending the Standard Model. Our group has built and installed three hardware systems for the experiment - a set of horizontal drift chambers, a set of luminosity monitors, and halo and low beam current monitoring detectors. During the period of this grant, we will maintain our hardware systems during data taking, analyze data, and extract physics results. We will also begin work on a newly approved TJNAF experiment to test the Standard Model - the MOLLER experiment - a precision measurement of the parity-violating asymmetry in the elastic scattering of polarized electrons on unpolarized electrons. The projects we are working on involve a wide range of hardware and software tasks that will contribute to the education of graduate and undergraduate students working on the project.