Precision Studies of the Standard Model using Parity-Violating Electron Scattering

使用违反宇称电子散射的标准模型的精度研究

• 批准号: 1714792
• 负责人: David Armstrong
• 金额: $ 60.8万
• 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: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1714792&HistoricalAwards=false
• 关键词: Precision; Studies; Standard; Model; using

In our quest to understand the fundamental structure of matter, physicists describe matter by its known elementary constituents: electrons, quarks, photons, gluons, etc. All experimentally observed elementary particles and their interactions are described by a theory known as the Standard Model of Particle Physics. Since its inception in the mid-1970s, the Standard Model of Particle Physics has been successful at describing a wide range of physical phenomena in nuclear and high energy physics, at accelerator laboratories and in table-top experiments. There are, however, compelling theoretical reasons to expect the Standard Model to break down, as well as some experimental hints in precision measurements. It is therefore widely believed that the Standard Model is simply an approximate low-energy description, arising from more fundamental physics that is manifest at energies that are currently beyond experimental reach. Precision measurements present a powerful approach to test the Standard Model of particle physics at low-energy electron accelerators. The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, is currently the world's leading laboratory for a subclass of these precision measurement tests of the Standard Model. This project supports precision measurements of the weak charge of the proton and of the electron in two large collaborative experiments at Jefferson Lab. In analogy to the electric charge, the weak charge describes how strongly these particles interact through the weak nuclear force. The results of both experiments, by themselves but also in combination with the results from the Large Hadron Collider at the European Organization for Nuclear Research (CERN), will allow us to constrain models of physics beyond the Standard Model. The investigators are working to increase economic and ethnic diversity in physics through specific recruiting and outreach efforts. One of the investigators has been active in improving gender diversity in physics through a national APS-affiliated organization, and is also developing a novel curricular track in Engineering Physics and Applied Design at William & Mary, which has a goal of attracting and improving retention of women and students of color to the STEM disciplines.The electroweak-mixing angle, a fundamental parameter in the Standard Model of Particle Physics, can be extracted at nuclear energies from measurements of the weak charge of the proton or of the electron. The mixing angle runs with energy scale in the Standard Model, and comparison of the measured value with the predicted running allows a sensitive search for physics beyond the Standard Model. The weak charges are accessed using parity-violating electron scattering in the Qweak experiment (for the proton) and the MOLLER experiment (for the electron). The Qweak experiment has taken data and the signature publication is currently in preparation. This will constitute the first precision measurement of the proton's weak charge. After publication of the main result, the experiment will finalize more than a dozen ancillary results. The investigators will continue their central role in the simulation and data analysis efforts crucial to the analysis of the backgrounds from electron-aluminum scattering and the polarization sensitivity of the main detectors. The MOLLER experiment is currently in the design stages and will use parity-violating electron-electron scattering to extract the electroweak mixing angle to a precision comparable to the best available high-energy measurements, through a measurement of the weak charge of the electron. The investigators will take a leading role in the development and testing of the track reconstruction detectors for the MOLLER experiment, and are also responsible for a detection system to measure the background from electro- and photo-produced pions.

为了了解物质的基本结构，物理学家通过其已知基本成分描述物质：电子，夸克，光子，胶子等。所有实验观察到的基本颗粒及其相互作用都被称为粒子物理的标准模型的理论描述。自1970年代中期成立以来，粒子物理学的标准模型已经成功地描述了核和高能物理学，加速器实验室和桌面实验中广泛的物理现象。但是，有令人信服的理论原因可以期望标准模型分解，以及精确测量中的一些实验提示。因此，人们普遍认为，标准模型仅仅是一个近似低能的描述，这是由更基本的物理学引起的，这些物理体现在当前无法实验的能量上。精度测量提出了一种强大的方法，可以测试低能电子加速器下粒子物理的标准模型。弗吉尼亚州纽波特新闻（Newport News）的托马斯·杰斐逊国家加速器设施（杰斐逊实验室）目前是全球领先的标准模型这些精确测量测试子类的领先实验室。该项目支持杰斐逊实验室的两个大型协作实验中质子和电子弱电荷的精确测量。与电荷类似，弱电荷描述了这些颗粒通过弱核力量的强烈相互作用。这两个实验的结果本身，还结合了欧洲核研究组织（CERN）的大型强子对撞机的结果，将使我们能够限制超出标准模型的物理模型。研究人员正在努力通过特定的招募和外展工作来提高物理学的经济和种族多样性。其中一位研究人员一直积极通过国家APS附属组织来改善物理学的性别多样性，并且还在William＆Mary在工程物理和应用设计方面开发了一条新的课程轨道，该课程的目标是吸引和提高妇女的保留率和提高型词干的妇女和学生的保留。质子或电子的电荷。混合角在标准模型中以能量尺度运行，并将测量值与预测的运行进行比较，可以对超出标准模型以外的物理进行敏感的搜索。使用QWEAK实验中（用于质子）和Moller实验（对于电子）中的平均侵略电子散射（对于电子）中，可以使用弱电荷进行访问。 QWEAK实验已获取数据，签名出版物目前正在准备中。这将构成对质子弱电荷的第一个精度测量。发表主要结果后，实验将最终确定十几个辅助结果。研究者将继续在模拟和数据分析工作中继续其核心作用，这对于对电子铝散射的背景和主要检测器的极化灵敏度至关重要。 Moller实验目前处于设计阶段，将使用奇偶校验电子 - 电子散射将电子混合角提取到与最佳可用高能测量值相当的精确度，并通过测量电子的弱电荷来提取。研究人员将在MOLLER实验的轨道重建探测器的开发和测试中发挥领导作用，并负责检测系统，以测量从电和照片产生的Pions的背景。

项目成果

Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering

前角弹性电子质子散射中束流法线单自旋不对称性的精密测量

• DOI: 10.1103/physrevlett.125.112502
• 发表时间: 2020
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: Androic, D.;Armstrong, D.S.;Asaturyan, A;Bartlett, K.;Beaufait, J.;Beminiwattha, R.S.;Benesch, J.;Benmokhtar, F.;Birchall, J.;Carlini, R.D.
• 通讯作者: Carlini, R.D.

Parity-violating inelastic electron-proton scattering at low Q2 above the resonance region

谐振区上方低 Q2 处的宇称破坏非弹性电子-质子散射

• DOI: 10.1103/physrevc.101.055503
• 发表时间: 2020
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Androić, D.;Armstrong, D. S.;Asaturyan, A.;Bartlett, K.;Beminiwattha, R. S.;Benesch, J.;Benmokhtar, F.;Birchall, J.;Carlini, R. D.;Cornejo, J. C.
• 通讯作者: Cornejo, J. C.

Measurement of the beam-normal single-spin asymmetry for elastic electron scattering from C12 and Al27

• DOI: 10.1103/physrevc.104.014606
• 发表时间: 2021-03
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: QWeak Collaboration D. Androic;D. Armstrong;A. Asaturyan;K. Bartlett;R. Beminiwattha;J. Benesch;F. Benmokhtar;J. Birchall;R. Carlini;M. Christy;J. Cornejo;S. Dusa;M. Dalton;C. Davis;W. Deconinck;J. Dowd;J. Dunne;D. Dutta;W. Duvall;M. Elassar;W. Falk;J. Finn;T. Forest;C. Gal;D. Gaskell;M. Gericke;V. Gray;F. Guo;J. Hoskins;D. Jones;M. Kargiantoulakis;P. King;E. Korkmaz;S. Kowalski;J. Leacock;J. Leckey;A. Lee;J. Lee;L. Lee;S. Macewan;D. Mack;J. Magee;R. Mahurin;J. Mammei;J. Martin;M. McHugh;D. Meekins;K. Mesick;R. Michaels;A. Mkrtchyan;H. Mkrtchyan;A. Narayan;L. Ndukum;Nuruzzaman;V. Nelyubin;W. Oers;V. Owen;S. Page;J. Pan;K. Paschke;S. Phillips;M. Pitt;R. Radloff;J. Rajotte;W. Ramsay;J. Roche;B. Sawatzky;T. Ševa;M. Shabestari;R. Silwal;N. Simicevic;G. Smith;P. Solvignon;D. Spayde;A. Subedi;R. Subedi;V. Tadevosyan;W. Tobias;B. Waidyawansa;P. Wang;S. Wells;S. Wood;P. Zang;S. Zhamkochyan

Measurement of the beam-normal single-spin asymmetry for elastic electron scattering from 12C and 27Al

12C 和 27Al 弹性电子散射束法向单自旋不对称性的测量

• 发表时间: 2021
• 期刊: Physical review
• 作者: Androic, D.;Armstrong, D.S.;Asaturyan, A;Bartlett, K.;Beaufait, J.;Beminiwattha, R.S.;Benesch, J.;Benmokhtar, F.;Birchall, J.;Carlini, R.D.
• 通讯作者: Carlini, R.D.

Determination of the Al27 Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement

通过宇称破坏电子散射测量确定 Al27 中子分布半径

• DOI: 10.1103/physrevlett.128.132501
• 发表时间: 2022
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Androić, D.;Armstrong, D. S.;Bartlett, K.;Beminiwattha, R. S.;Benesch, J.;Benmokhtar, F.;Birchall, J.;Carlini, R. D.;Cornejo, J. C.;Covrig Dusa, S.
• 通讯作者: Covrig Dusa, S.