Probing Nucleon Structure Through Muon and Photon Scattering

通过 μ 子和光子散射探测核子结构

基本信息

批准号：
1714833
负责人：
Evangeline Downie
金额：
$ 42万
依托单位：
George Washington University
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：
2017-08-15 至 2020-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1714833&HistoricalAwards=false
关键词：
Probing Nucleon Structure Through Muon

项目摘要

Protons, neutrons, and electrons are the building blocks of all matter with which we are most familiar. Despite the scientific efforts to comprehend their nature, there are many things about them that remain to be understood. In 2010, a measurement of the size of the proton resulted in a proton size measurement much smaller than expected. This measurement disagreed with, but was much more precise than, all the other proton size measurements to date. The research supported by this award aims to resolve this issue, known as the "Proton Radius Puzzle" by making a simultaneous measurement of muon and electron scattering on the proton in the Muon Proton Scattering Experiment (MUSE). In addition to determining the proton size, the group will spend a small amount of its time investigating the internal structures and dynamics of the proton and neutron, by measuring quantities known as the polarizabilities. These measurements will be made by scattering light from protons and neutrons. Experiments will take place at laboratories in Switzerland, Germany and the US. Through these experiments, in addition to gaining knowledge about protons and neutrons, the postdoctoral researchers, undergraduate, and graduate students will gain knowledge and experience of modern detection techniques, and simulation and reconstruction software, which are employed in many applications such as industrial or medical imaging. They will also participate in cultural exchanges with researchers from many countries worldwide, and develop their communication, organization and leadership skills.MUSE will make the world's first measurement of the proton radius via elastic muon scattering at a precision which can address the 4% proton radius puzzle. The experiment will be performed at the Paul Scherer Institute in Switzerland. The simultaneous measurement of elastic e-plus / e-minus and mu-plus/mu-minus scattering on the proton in the MUSE experiment will allow resolution of the proton radius puzzle: the 7-sigma discrepancy between the charge radius of the proton measured in the excitation spectrum of muonic hydrogen and that measured in the excitation spectrum of the atomic hydrogen. The polarizabilities of the proton and neutron will be also investigated via their influence on beam and target polarization asymmetries measured in Compton Scattering. Precise cross section measurements on liquid hydrogen and helium three and four within the A2 collaboration at the Mainzer Microtron in Mainz, Germany, and at lower energies in the High-Intensity Gamma Source (HIGS) at the Triangle Universities Nuclear Laboratory. This project involves participation in and leadership of construction, data taking and analysis of MUSE through the support of the PI, a graduate student, and postdoc. It will result in precise, simultaneous elastic muon and electron scattering data, and precise measurements of the scalar polarizabilities of the proton and neutron.

质子、中子和电子是我们最熟悉的所有物质的组成部分。尽管科学界努力理解它们的本质，但关于它们的许多事情仍有待理解。 2010年，对质子尺寸的测量结果显示，质子尺寸测量结果比预期小得多。该测量结果与迄今为止所有其他质子尺寸测量结果不一致，但更为精确。该奖项支持的研究旨在通过在μ子质子散射实验（MUSE）中同时测量质子上的μ子和电子散射来解决这个被称为“质子半径之谜”的问题。除了确定质子大小之外，该小组还将花费少量时间通过测量极化率来研究质子和中子的内部结构和动力学。这些测量将通过质子和中子的散射光进行。实验将在瑞士、德国和美国的实验室进行。通过这些实验，除了获得有关质子和中子的知识外，博士后研究人员、本科生和研究生还将获得现代检测技术以及模拟和重建软件的知识和经验，这些技术在工业或医学等许多应用中都有应用。成像。他们还将参与与世界多个国家的研究人员的文化交流，培养他们的沟通、组织和领导能力。MUSE将在世界上首次通过弹性介子散射测量质子半径，其精度可测量4%的质子半径谜。该实验将在瑞士保罗谢勒研究所进行。在 MUSE 实验中同时测量质子上的弹性 e-plus / e-minus 和 mu-plus/mu-minus 散射将能够解决质子半径难题：测量的质子电荷半径之间的 7-sigma 差异μ子氢的激发光谱和原子氢的激发光谱中测量的结果。还将通过质子和中子对康普顿散射中测量的光束和目标极化不对称性的影响来研究质子和中子的极化率。在德国美因茨 Mainzer Microtron 的 A2 合作项目中以及三角大学核实验室的高强度伽马源 (HIGS) 中的低能量下，对液氢和氦三和四进行了精确的横截面测量。该项目涉及在 PI、研究生和博士后的支持下参与和领导 MUSE 的建设、数据采集和分析。它将产生精确、同步的弹性μ子和电子散射数据，以及质子和中子标量极化率的精确测量。

项目成果

期刊论文数量（11）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Near-threshold π− photoproduction on the deuteron

氘核上的近阈值摄影制作

DOI：
10.1103/physrevc.101.035207
发表时间：
2020-03
期刊：
Physical Review C
影响因子：
3.1
作者：
Strandberg, B.;Fissum, K. G.;Annand, J. R.;Briscoe, W. J.;Brudvik, J.;Cividini, F.;Clark, L.;Downie, E. J.;England, K.;Feldman, G.;et al
通讯作者：
et al

New Insight in the Q2 Dependence of Proton Generalized Polarizabilities

对质子广义极化率第二季度依赖性的新见解

DOI：
10.1103/physrevlett.123.192302
发表时间：
2019-11
期刊：
Physical Review Letters
影响因子：
8.6
作者：
Beričič, J.;Correa, L.;Benali, M.;Achenbach, P.;Ayerbe Gayoso, C.;Bernauer, J. C.;Blomberg, A.;Böhm, R.;Bosnar, D.;Debenjak, L.;et al
通讯作者：
et al

Compton scattering from the deuteron above pion-production threshold

来自高于π介子产生阈值的氘核的康普顿散射

DOI：
10.1103/physrevc.98.012201
发表时间：
2018-07
期刊：
Physical Review C
影响因子：
3.1
作者：
Strandberg, B.;Annand, J. R.;Briscoe, W.;Brudvik, J.;Cividini, F.;Clark, L.;Downie, E. J.;England, K.;Feldman, G.;Fissum, K. G.;et al
通讯作者：
et al

Timing detectors with SiPM read-out for the MUSE experiment at PSI

用于 PSI 的 MUSE 实验的具有 SiPM 读出功能的定时探测器

DOI：
10.1016/j.nima.2020.164801
发表时间：
2021-01
期刊：
Detectors and Associated Equipment
影响因子：
0
作者：
Rostomyan, T.;Cline, E.;Lavrukhin, I.;Atac, H.;Atencio, A.;Bernauer, J.C.;Briscoe, W.J.;Cohen, D.;Cohen, E.O.;Collicott, C.;et al
通讯作者：
et al

Cross section for γn→π0n measured at the Mainz A2 experiment

在美因茨 A2 实验中测量的 γn 至 0n 的横截面

DOI：
10.1103/physrevc.100.065205
发表时间：
2019-12
期刊：
Physical Review C
影响因子：
3.1
作者：
Briscoe, W. J.;Hadžimehmedović, M.;Kudryavtsev, A. E.;Kulikov, V. V.;Martemianov, M. A.;Strakovsky, I. I.;Švarc, A.;Tarasov, V. E.;Workman, R. L.;Abt, S.;et al
通讯作者：
et al