Collaborative Research: Apparatus for Normalization and Systematic Control of the MOLLER Experiment

合作研究：莫勒实验标准化和系统控制装置

• 批准号: 2012724
• 负责人: David Armstrong
• 金额: $ 76.11万
• 依托单位: College of William and Mary
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2012724&HistoricalAwards=false
• 关键词: Collaborative; Research; Apparatus; Normalization; Systematic

A central goal of nuclear and particle physics is to obtain a complete understanding of the fundamental constituents of matter and the forces through which they interact. The Standard Model (SM) of particle physics has proven remarkably successful at describing the interactions of the known fundamental particles for the past 50 years. However, the SM is known to be incomplete, and there are compelling reasons to expect that the SM will eventually fail to describe some observed properties of matter. To address the question of whether there is new physics beyond the Standard Model, a precision measurement of the weak charge of the electron will be performed in a collaborative experiment at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. The electron’s weak charge is the weak force analog of the common electric charge of the electron, and it is precisely predicted in the SM. Any deviation of the measurement from this prediction would be evidence for undiscovered phenomena that represent new physics beyond our current understanding. The experiment is named MOLLER and it comprises a range of hardware design and construction activities as well as software development which will provide excellent training for students and young scientists. The experience of working in a collaborative modern science enterprise with state of the art technology provides a strong basis for a variety of careers.The funds provided by this project will support construction of essential apparatus for the MOLLER experiment (Measurement of a Lepton-Lepton Electroweak Reaction) at Jefferson Lab. MOLLER will measure the electron’s neutral weak charge by making a precision measurement of the parity-violating asymmetry in the elastic scattering of polarized electrons on unpolarized electrons at very low momentum transfer. This will result in a determination of the weak mixing angle at low energy with a precision comparable to the best determinations from high energy colliders, providing excellent sensitivity to physics scenarios that extend beyond the Standard Model. The MOLLER experiment consists of three major subsystems: 1) the beam/target/spectrometer to prepare the scattered Møller electrons to be observed, 2) apparatus to measure the raw parity-violating asymmetry to the needed statistical precision, and 3) apparatus for Normalization and Systematic Control to achieve sub-ppb and sub-% level systematic uncertainty and normalization control goals. The collaborative project described in this proposal will develop subsystem #3; namely the design, construction, and testing of the MOLLER Normalization and Systematic Control apparatus. The work will be done over the period December 2020 – November 2024. This includes the tracking system, background detectors, auxiliary asymmetry measurement detectors, and certain aspects of beam monitoring/control and beam polarimetry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

核物理和粒子物理学的一个核心目标是完全了解物质的基本构成以及它们相互作用的力。事实证明，粒子物理学的标准模型（SM）在描述了过去50年来描述已知基本颗粒的相互作用方面取得了非常成功。但是，已知SM是不完整的，并且有令人信服的理由可以期望SM最终无法描述物质的某些特性。为了解决除标准模型之外是否还有新物理学的问题，将在弗吉尼亚州纽波特新闻的托马斯·杰斐逊国家加速器设施的协作实验中对电子的弱点进行精确测量。电子的弱电荷是电子的常见电荷的弱力类似物，并且在SM中得到了精确预测。测量结果与该预测的任何偏差都将是未发现现象的证据，这代表了我们当前理解超出我们当前理解的新物理。该实验被称为Moller，它包括一系列硬件设计和施工活动以及软件开发，可为学生和年轻科学家提供出色的培训。与最先进的技术在合作的现代科学企业中工作的经验为各种职业提供了强大的基础。该项目提供的资金将支持杰斐逊实验室的Moller实验（测量Lepton-Lepton-Lepton Electroweak反应的测量）的基本设备的建设。 Moller将通过在非常低的动量传递下对偏振电子的弹性散射中的平均侵略不对称性进行精确测量，以测量电子的中性弱电荷。这将导致在低能量下的弱混合角，具有与高能量山针的最佳测定相当的精确度，从而对物理场景提供了极好的敏感性，而物理场景超出了标准模型。 Moller实验由三个主要子系统组成：1）梁/目标/光谱仪准备要观察到的分散的Møller电子设备，2）测量对所需统计精确的原始平等性侵犯不对称的设备，以及3）设备，用于正常化和系统控制，以实现子PPPB和次级级别的系统层面化量和正常化的系统范围和正常化的系统。本提案中描述的协作项目将开发子系统＃3；即Moller归一化和系统控制设备的设计，结构和测试。这项工作将在2020年12月至2024年11月的时间内完成。这包括跟踪系统，背景探测器，辅助不对称测量探测器以及光束监控/控制和光束极化的某些方面。该奖项反映了NSF的立法任务，并通过使用基础的智力效果和广泛的影响来评估支持，并被视为诚实。