NSF-BSF: Exploring the Proton Radius Puzzle and Phenomena Beyond the Standard Model with Low-energy Lepton Scattering

NSF-BSF：利用低能轻子散射探索质子半径之谜和超越标准模型的现象

• 批准号: 1812402
• 负责人: Michael Kohl
• 金额: $ 69.6万
• 依托单位: Hampton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1812402&HistoricalAwards=false
• 关键词: NSF; BSF; Exploring; Proton; Radius

This award provides funding for Dr. Michael Kohl and his group at Hampton University, a Historically Black College und University in Virginia, USA. The group has a core function in the Muon Scattering Experiment (MUSE) in preparation at Paul-Scherrer Institute in Switzerland, and in the DarkLight project at the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) in the US. The MUSE project is a dedicated investigation of the so-called proton radius puzzle, a very prominent topic in nuclear physics. The experiment will measure the proton charge radius with high precision via lepton-proton elastic scattering, and will compare the interactions of muons and electrons of either charge with the proton at a fundamental level. The experiment will severely constrain possible explanations of the puzzle and has the potential to reveal new physics beyond the Standard Model. The DarkLight experiment in preparation at Jefferson Lab aims to discover a new particle associated with a fifth interaction suited to explain several observed anomalies in particle physics while offering a connection to dark matter. Both projects offer high-profile opportunities for students and postdocs at the forefront of international nuclear and particle physics research. The PI's research program has many facets and offers excellent opportunities for cutting-edge education and research purpose domestically and abroad. This proposal combines state-of-the-art detector development at Hampton University with its application in forefront research at PSI and at Jefferson Lab. This provides new research and educational opportunities at first-class research facilities for students from minority populations, predominantly African-Americans, and postdoctoral researchers. The development and operation of GEM detectors in the MUSE and DarkLight environments will be beneficial to advance this still novel technology with potential future applications in other experiments, as well as in the medical sector. The MUSE experiment has been proposed and approved to provide key insight in the quest to explain the so-called proton radius puzzle - the over five-standard deviation discrepancy between proton charge radius measurements with electronic and muonic probes, respectively. Possible explanations also include new physics beyond the Standard Model. The MUSE experiment aims to address one of the most pressing questions in nuclear and particle science to date. MUSE uses mixed muon and electron beams of either charge (mu+, e+, mu-, e-) to make precise measurements of the lepton-proton elastic scattering cross sections and proton form factors, with the goal to extract the proton charge radius for each probe. It will determine with the highest precision, model independently and conclusively, if there is any proton charge radius difference observed in electron versus muon scattering. At the same time it will determine the role of two-photon exchange and provide tight constraints on theory. Dr. Kohl is one of the co-initiators of the MUSE project. The role of Dr. Kohl's group in MUSE is essential to this project. This project focuses on the challenging task of high-resolution beam particle tracking at MUSE with GEM detectors, in a way not done before at low beam energies. The tracker is exposed to high rate density and beam flux, and needs to operate efficiently at a trigger rate of a few kHz. The DarkLight Phase-I project at Jefferson Lab includes a focused search for a dark photon or neutral boson in the mass region around 17 MeV/c2, where evidence for a fifth-force carrier has been reported.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.

该奖项为美国弗吉尼亚州汉普顿大学的迈克尔·科尔博士和他的团队提供资金，汉普顿大学是一所历史悠久的黑人学院和大学。该小组在瑞士保罗谢勒研究所准备的μ介子散射实验（MUSE）和美国托马斯杰斐逊国家加速器设施（杰斐逊实验室）的暗光项目中发挥着核心作用。 MUSE 项目专门研究所谓的质子半径之谜，这是核物理学中一个非常突出的话题。该实验将通过轻子-质子弹性散射高精度测量质子电荷半径，并在基本水平上比较任一电荷的μ子和电子与质子的相互作用。该实验将严重限制对这个难题的可能解释，并有可能揭示标准模型之外的新物理学。杰斐逊实验室正在准备的暗光实验旨在发现一种与第五种相互作用相关的新粒子，该粒子适合解释粒子物理学中观察到的几个异常现象，同时提供与暗物质的联系。这两个项目都为国际核物理和粒子物理研究前沿的学生和博士后提供了备受瞩目的机会。 PI 的研究项目涉及多个方面，为国内外尖端教育和研究目的提供了绝佳的机会。该提案将汉普顿大学最先进的探测器开发与其在 PSI 和杰斐逊实验室的前沿研究中的应用结合起来。这为少数族裔（主要是非裔美国人）的学生和博士后研究人员提供了一流研究设施的新研究和教育机会。在 MUSE 和 DarkLight 环境中开发和运行 GEM 探测器将有利于推进这项仍然新颖的技术，并在其他实验以及医疗领域具有潜在的未来应用。 MUSE 实验已被提出并获得批准，旨在为解释所谓的质子半径难题（电子探针和 μ 子探针分别测量质子电荷半径之间超过五个标准偏差的差异）提供关键见解。可能的解释还包括标准模型之外的新物理学。 MUSE 实验旨在解决迄今为止核科学和粒子科学中最紧迫的问题之一。 MUSE 使用任一电荷（mu+、e+、mu-、e-）的混合 μ 子束和电子束来精确测量轻子-质子弹性散射截面和质子形状因子，目标是提取每个电荷的质子电荷半径探测。它将以最高精度、独立且最终的模型确定电子与μ子散射中是否观察到任何质子电荷半径差异。同时它将确定双光子交换的作用并提供严格的理论约束。 Kohl 博士是 MUSE 项目的联合发起人之一。 Kohl 博士的团队在 MUSE 中的作用对于该项目至关重要。该项目的重点是在 MUSE 上使用 GEM 探测器进行高分辨率束粒子跟踪这一具有挑战性的任务，这是以前在低束能量下从未完成过的。跟踪器暴露在高速率密度和光束通量下，并且需要在几 kHz 的触发速率下高效运行。杰斐逊实验室的 DarkLight 第一阶段项目包括在 17 MeV/c2 左右的质量区域集中搜索暗光子或中性玻色子，其中已经报告了第五力载体的证据。该奖项反映了 NSF 的法定使命，并已通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Ruling out Color Transparency in Quasielastic C12(e,e′p) up to Q2 of 14.2 (GeV/c)2

排除准弹性 C12(e,e−p) 中 Q2 的颜色透明度达到 14.2−−(GeV/c)2

• DOI: 10.1103/physrevlett.126.082301
• 发表时间: 2021
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Bhetuwal, D.;Matter, J.;Szumila-Vance, H.;Kabir, M. L.;Dutta, D.;Ent, R.;Abrams, D.;Ahmed, Z.;Aljawrneh, B.;Alsalmi, S.
• 通讯作者: Alsalmi, S.

Instrumental uncertainties in radiative corrections for the MUSE experiment

MUSE 实验辐射校正中的仪器不确定性

• DOI: 10.1140/epja/s10050-023-01215-0
• 发表时间: 2024
• 期刊: The European Physical Journal A
• 作者: Li, L.;Strauch, S.;Bernauer, J. C.;Briscoe, W. J.;Christopher Ndukwe, A.;Cline, E.;Cohen, D.;Deiters, K.;Downie, E. J.;Fernando, I. P.
• 通讯作者: Fernando, I. P.

Performance check of the CsI(Tl) calorimeter for the J-PARC E36 experiment by observing e+ from muon decay

通过观察 μ 子衰变中的 e 来检查 J-PARC E36 实验中 CsI(Tl) 量热仪的性能

• DOI: 10.1016/j.nima.2018.05.065
• 发表时间: 2018
• 期刊: Detectors and Associated Equipment
• 作者: Ito, H.;Horie, K.;Shimizu, S.;Bianchin, S.;Djalali, C.;Dongwi, B.;Gill, D.;Hasinoff, M.D.;Igarashi, Y.;Imazato, J.
• 通讯作者: Imazato, J.

Measurement of structure dependent radiative K+ → e+νγ decays using stopped positive kaons

使用停止的正 kaons 测量结构依赖的辐射 K α γ 衰变

• DOI: 10.1016/j.physletb.2022.136913
• 发表时间: 2022
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: Ito, H.;Kobayashi, A.;Bianchin, S.;Cao, T.;Djalali, C.;Dongwi, D.H.;Gautam, T.;Gill, D.;Hasinoff, M.D.;Horie, K.
• 通讯作者: Horie, K.

Design and operation of a windowless gas target internal to a solenoidal magnet for use with a megawatt electron beam

• DOI: 10.1016/j.nima.2019.05.071
• 发表时间: 2019-03
• 期刊: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• 作者: S. Lee;R. Corliss;I. Friščić;R. Alarcon;S. Aulenbacher;J. Balewski;S. Benson;J. Bernauer;J. Bessuille;J. Boyce;J. Coleman;D. Douglas;C. Epstein;P. Fisher;S. Frierson;M. Garçon;J. Grames;D. Hasell;C. Hernández-García;E. Ihloff;R. Johnston;K. Jordan;R. Kazimi;J. Kelsey;M. Kohl;A. Liyanage;M. McCaughan;R. Milner;P. Moran;J. Nazeer;D. Palumbo;M. Poelker;G. Randall;S. Steadman;C. Tennant;C. Tschalär;C. Vidal;C. Vogel;Yayu Wang;S. Zhang