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.

了解夸克和胶子如何将自己局限于产生元素的中子和质子中，以及在粒子物理学的标准模型（SM）之外寻找新物理学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（Jefferson Lab）执行两个尖端的实验，即Primex-Eta和Jlab ETA工厂（JEF），以探索以前无法实现的敏感性的两个基本主题。这些测量结果将阐明一些基本问题：量子Chromo动态限制的起源和动态是什么？占物质85％的暗物质的性质是什么？在宇宙中观察到物质和反物质的不对称性的原因是什么？该项目的范围，包括硬件开发，实际实验和数据分析的性能，将为博士后研究员和一组本科生提供高级培训。学生将获得动手实验技术，数据分析和计算的重要技能，以及批判性思维和解决问题的能力，以履行本科课程，并为STEM领域的职业做好准备。在杰斐逊实验室（Jefferson Lab）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观点。该项目的女性PI是榜样，并促进了茎场中的多样性和包容性。 Primex-Eta实验将使用现有的gluex设备，其新型热量表由12x12 PBWO4晶体阵列组成。它将使用Primakoff效应和E+E-碰撞在先前的实验结果之间解决长期的差异（〜3σ），并将提供对光夸克质量比和η-η'Inging角的准确确定。 JEF实验将测量各种η和ηꞌ衰变，重点是稀有模式，与所有先前的实验相比，具有两个数量级的背景抑制作用的干净数据集。除了基线粘合剂设备外，JEF实验还需要升级的前向量热计（FCAL-II），具有高颗粒性，高分辨率的PBWO4晶体核心的中央区域中，以最大程度地减少淋浴重叠并优化能量和位置的分辨率。从JEF实验中收集的数据将提供敏感的问题：（a）首次探讨标量梅森动力学在手性扰动理论中的作用； （b）通过η→3πdalitz分布拧紧光夸克质量比的不确定性； （c）通过改善现有边界的两个以上的数量级来搜索各种子gev深色仪孔候选者（包括向量，标量和类似轴突的颗粒），并在全球范围内的高能撞机机和地下设施中均已完成。 （d）为C-侵略，p的新力量提供最佳的直接限制。作为实验演讲者，PI将在Primex-Eta和JEF中发挥领导作用。 PI和她的团队将：（1）分析Primex-Eta的I阶段运行中收集的数据，准备并在2021年秋季进行II期运行； （2）开发升级的FCAL-II，并准备2024年预期运行的JEF实验； （3）继续服务责任，以维持和操作低粒度对配对仪检测器，以控制Hall D的光子通量D。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子和更广泛的影响评估标准来评估NSF的法定任务。

项目成果

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.

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

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.

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.