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.

该奖项为迈克尔科尔博士和他在汉普顿大学的小组提供资金，汉普顿大学是美国弗吉尼亚州一所历史上的黑人学院和大学。该小组在瑞士Paul-Scherrer研究所准备的μ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）的暗光项目中发挥核心作用。MUSE项目是对所谓的质子半径之谜的专门调查，这是核物理学中一个非常突出的主题。该实验将通过轻子-质子弹性散射高精度地测量质子电荷半径，并将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谜题的可能解释，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，这种相互作用适合解释粒子物理学中观察到的几种异常现象，同时提供与暗物质的联系。这两个项目都为处于国际核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的研究计划有许多方面，并为国内外的尖端教育和研究目的提供了极好的机会。该提案结合了汉普顿大学最先进的探测器开发及其在PSI和杰斐逊实验室前沿研究中的应用。这为来自少数民族人口，主要是非洲裔美国人和博士后研究人员的学生提供了新的研究和教育机会。GEM探测器在MUSE和DarkLight环境中的开发和运行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中具有潜在的未来应用。MUSE实验已经被提出并被批准为解释所谓的质子半径之谜提供关键的见解-分别用电子和μ子探针测量质子电荷半径之间超过5个标准差的差异。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，目的是提取每个探针的质子电荷半径。它将以最高的精度，独立和决定性地确定模型，如果在电子与μ子散射中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。科尔博士是MUSE项目的共同发起人之一。科尔博士的小组在MUSE中的作用对这个项目至关重要。该项目的重点是在MUSE使用GEM探测器进行高分辨率束粒子跟踪的挑战性任务，这是以前在低束能量下从未做过的。跟踪器暴露于高速率密度和束流，并且需要在几kHz的触发速率下有效地操作。杰斐逊实验室的暗光第一阶段项目包括在质量约为17 MeV/c2的区域内重点寻找暗光子或中性玻色子，其中有证据表明存在第五力载体。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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

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.

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.

Detector response of Cherenkov radiators for calorimetry in the energy range below 14 MeV

• DOI: 10.1016/j.nima.2020.163665
• 发表时间: 2020-04
• 期刊: Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
• 影响因子: 1.4
• 作者: M. Christmann;P. Burger;P. Achenbach;S. Aulenbacher;M. Ball;S. Baunack;J. Bernauer;M. Biroth;P. Brand;S. Caiazza;E. Cline;A. Denig;L. Doria;I. Friščić;J. Geimer;P. Gülker;A. Khoukaz;M. Kohl;T. Kolar;M. Lauss;W. Lauth;M. Littich;M. Lupberger;S. Lunkenheimer;F. Maas;M. Mauch;H. Merkel;M. Mihovilovič;R. Milner;J. Müller;J. Rausch;B. Schlimme;C. Sfienti;S. Širca;S. Stengel;C. Szyszka;S. Vestrick;Y. F. Wang

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

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.