Precision Tests of Fundamental Physics via Light Pseudoscalar Mesons

通过光赝标量介子进行基础物理的精密测试

• 批准号: 2111181
• 负责人: Liping Gan
• 金额: $ 45.98万
• 依托单位: University of North Carolina at Wilmington
• 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: 2021-07-15 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2111181&HistoricalAwards=false
• 关键词: Precision; Tests; Fundamental; Physics; via

Understanding how quarks and gluons confine themselves into the neutrons and protons that make the elements, and searching for new physics beyond the Standard Model (SM) of particle physics are two frontiers in physics. The primary goal of this project is to perform two cutting-edge experiments, PrimEx-eta and JLab Eta Factory (JEF), at Jefferson Lab to explore both fundamental topics with sensitivities not previously achievable. These measurements will shed light on some fundamental questions: What is the origin and dynamics of Quantum Chromo Dynamic confinement? What is the nature of dark matter that constitutes 85% of matter and what is the cause for the asymmetry of matter and antimatter observed in the universe? The scope of this project, including hardware development, performance of the actual experiment and data analysis, will provide advanced training for a postdoctoral researcher and a group of undergraduate students. Students will acquire significant skills in hands-on experimental techniques, data analysis and computation, as well as critical thinking and problem-solving abilities to fulfill the undergraduate curricula and prepare them for careers in STEM fields. The opportunities for young researchers (postdoc and students) working at Jefferson Lab will enhance their experience and global perspectives. The female PI of this project serves as a role model and promotes diversity and inclusion in the STEM fields. The PrimEx-eta experiment will measure the η radiative decay width at ~3% precision via the Primakoff effect, using the existing GlueX apparatus with a new calorimeter consisting of 12x12 array of PbWO4 crystals. It will resolve a longstanding discrepancy (~3σ) between the previous experimental results using the Primakoff effect and e+e- collisions, and will offer accurate determinations of the light quark-mass ratio and the η-η' mixing angle. The JEF experiment will measure various η and ηꞌ decays with emphasis on rare modes, producing a clean dataset with background suppression of a factor of two orders of magnitude compared to all previous experiments. In addition to the baseline GlueX apparatus, the JEF experiment will require an upgraded forward calorimeter (FCAL-II) with a high-granularity, high-resolution PbWO4 crystal core in the central region that minimizes shower overlaps and optimizes the resolutions of energy and position. The data collected from the JEF experiment will provide sensitive probes to: (a) explore the role of scalar meson dynamics in chiral perturbation theory for the first time; (b) tighten the uncertainty in the light quark mass ratio by the η→3π Dalitz distributions; (c) search for various sub-GeV dark gauge boson candidates (including vectors, scalars and Axion-like particles) by improving the existing bounds by more than two orders of magnitude and is complementary to the ongoing worldwide efforts at high-energy collider and underground facilities; and (d) provide the best direct constraints for C-violating, P-conserving new forces. As an experiment spokesperson, the PI will play a leadership role in both PrimEx-eta and JEF. The PI and her team will: (1) analyze the data collected in the phase I run of PrimEx-eta, prepare and perform the phase II run in fall 2021; (2) develop an upgraded FCAL-II and prepare the JEF experiment for the anticipated run in 2024; (3) continue the service responsibility for maintaining and operating the low-granularity pair spectrometer detectors to control the photon flux in Hall D.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.

了解夸克和胶子是如何将自己限制在构成元素的中子和质子中的，以及在粒子物理的标准模型(SM)之外寻找新的物理是物理学的两个前沿。该项目的主要目标是在杰斐逊实验室进行两个尖端实验，PrimeX-ETA和JLab Eta Factory(JEF)，以探索这两个具有以前无法实现的敏感性的基本主题。这些测量将阐明一些基本问题：量子色度动态限制的起源和动力学是什么？构成85%物质的暗物质的性质是什么？宇宙中观察到的物质和反物质不对称的原因是什么？该项目的范围包括硬件开发、实际实验性能和数据分析，将为一名博士后研究员和一批本科生提供高级培训。学生将获得动手实验技术、数据分析和计算方面的重要技能，以及批判性思维和解决问题的能力，以完成本科课程并为在STEM领域的职业生涯做好准备。在杰斐逊实验室工作的年轻研究人员(博士后和学生)的机会将增强他们的经验和全球视野。该项目的女性PI作为榜样，促进STEM领域的多样性和包容性。η辐射衰变宽度测量实验将利用现有的GlueX装置和由12×12的PbWO_4晶体阵列组成的新量能器，通过Primakoff效应以~3%的精度测量。它将解决之前使用普里马科夫效应和e+e碰撞的实验结果之间的长期不一致(~3σ)，并将提供对轻夸克质量比和η-η混合角的准确确定。JEF实验将测量各种η和ηꞌ衰变，重点是罕见模式，产生一个干净的数据集，与之前的所有实验相比，背景抑制因子是两个数量级。除了基线GlueX仪器，JEF实验将需要一个升级的前向量热计(FCAL-II)，在中心区域具有高粒度、高分辨率的PbWO4晶体核心，以最大限度地减少簇射重叠，并优化能量和位置的分辨率。从JEF实验收集的数据将提供灵敏的探测器来：(A)首次探索标量介子动力学在手征微扰理论中的作用；(B)通过η→3πDalitz分布收紧轻夸克质量比的不确定性；(C)通过将现有的界限改进两个数量级以上来寻找各种亚GeV暗规范玻色子(包括矢量、标量和轴子类粒子)，这将是对目前全世界在高能对撞机和地下设施上进行的努力的补充；以及(D)为C破坏、P守恒的新作用力提供最佳的直接约束。作为实验发言人，PI将在PrimeX-ETA和JEF中发挥领导作用。PI和她的团队将：(1)分析在PrimeX-ETA第一阶段运行中收集的数据，准备并执行2021年秋季的第二阶段运行；(2)开发升级的FCAL-II，并为2024年的预期运行准备JEF实验；(3)继续负责维护和操作低粒度对光谱仪探测器，以控制D厅的光子流量。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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

Search for photoproduction of axionlike particles at GlueX

• DOI: 10.1103/physrevd.105.052007
• 发表时间: 2021-09
• 期刊: Physical Review D
• 影响因子: 5
• 作者: S. Adhikari;C. Akondi;M. Albrecht;A. Ali;M. Amaryan;A. Asaturyan;A. Austregesilo;Z. Baldwin;F. Barbosa;J. Barlow;E. Barriga;R. Barsotti;T. Beattie;V. Berdnikov;T. Black;W. Boeglin;W. Briscoe;T. Britton;W. Brooks;E. Chudakov;S. Cole;P. Cole;O. Cortes;V. Crede;M. Dalton;A. Deur;S. Dobbs;A. Dolgolenko;R. Dotel;M. Dugger;R. Dzhygadlo;D. Ebersole;H. Egiyan;T. Erbora;A. Ernst;P. Eugenio;C. Fanelli;S. Fegan;J. Fitches;A. Foda;S. Furletov;L. Gan;H. Gao;A. Gasparian;C. Gleason;K. Goetzen;V. Goryachev;L. Guo;M. Hagen;H. Hakobyan;A. Hamdi;J. Hernandez;N. Hoffman;G. Hou;G. Huber;A. Hurley;D. Ireland;M. Ito;I. Jaegle;N. Jarvis;R. T. Jones-R. T.-Jones-2213399303;V. Kakoyan;G. Kalicy;M. Kamel;V. Khachatryan;M. Khatchatryan;C. Kourkoumelis;S. Kuleshov;A. LaDuke;I. Larin;D. Lawrence;D. Lersch;H. Li;W. B. Li-W. B.-Li-2124567731;Bo Liu;K. Livingston;G. Lolos;L. Lorenti;K. Luckas;V. Lyubovitskij;D. Mack;A. Mahmood;H. Marukyan;V. Matveev;M. McCaughan;M. McCracken;C. Meyer;R. Miskimen;R. Mitchell;K. Mizutani;V. Neelamana;F. Nerling;L. Ng;A. Ostrovidov;Z. Papandreou;C. Paudel;P. Pauli;R. Pedroni;L. Pentchev;K. Peters;J. Reinhold;B. Ritchie;J. Ritman;G. Rodriguez;D. Romanov;C. Romero;K. Saldaña;C. Salgado;S. Schadmand;A. Schertz;A. Schick;A. Schmidt;R. Schumacher;J. Schwiening;P. Sharp;X. Shen;M. Shepherd;A. Smith;E. Smith;D. Sober;A. Somov;S. Somov;O. Soto;J. Stevens;I. Strakovsky;B. Sumner;K. Suresh;V. Tarasov;S. Taylor;A. Teymurazyan;A. Thiel;G. Vasileiadis;T. Viducic;T. Whitlatch;N. Wickramaarachchi;M. Williams;Y. Yang;S. Yoon;J. Zarling;Z. Zhang;Z. Zhao;J. Zhou;X. Zhou;B. Zihlmann

Measurement of spin density matrix elements in Λ(1520) photoproduction at 8.2–8.8 GeV

8.2–8.8 GeV Î(1520) 光制作中自旋密度矩阵元素的测量

• DOI: 10.1103/physrevc.105.035201
• 发表时间: 2022
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Adhikari, S.;Akondi, C. S.;Albrecht, M.;Ali, A.;Amaryan, M.;Asaturyan, A.;Austregesilo, A.;Baldwin, Z.;Barbosa, F.;Barlow, J.
• 通讯作者: Barlow, J.

Measurement of R=σL/σT and the separated longitudinal and transverse structure functions in the nucleon-resonance region

R=ÏL/ÏT 的测量以及核子共振区域中分离的纵向和横向结构函数

• DOI: 10.1103/physrevc.105.065205
• 发表时间: 2022
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Liang, Y.;Tvaskis, V.;Christy, M. E.;Ahmidouch, A.;Armstrong, C. S.;Arrington, J.;Asaturyan, R.;Avery, S.;Baker, O. K.;Beck, D. H.
• 通讯作者: Beck, D. H.

Electromagnetic calorimeters based on scintillating lead tungstate crystals for experiments at Jefferson Lab

基于闪烁钨酸铅晶体的电磁量热仪，用于杰斐逊实验室的实验

• DOI: 10.1016/j.nima.2021.165683
• 发表时间: 2021
• 期刊: Detectors and Associated Equipment
• 作者: Asaturyan, A.;Barbosa, F.;Berdnikov, V.;Chudakov, E.;Crafts, J.;Egiyan, H.;Gan, L.;Gasparian, A.;Harding, K.;Horn, T.
• 通讯作者: Horn, T.