NSF-BSF: The Study of Nuclear Physics with Intermediate Energy Probes

NSF-BSF：利用中能探针进行核物理研究

• 批准号: 2111050
• 负责人: Yordanka Ilieva
• 金额: $ 135万
• 依托单位: University of South Carolina at Columbia
• 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: 2021-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2111050&HistoricalAwards=false
• 关键词: NSF; BSF; Study; Nuclear; Physics

Although ninety-eight percent of the mass of ordinary matter is due to the strong subatomic force, the present theory of that force (Quantum Chromodynamics) is still not fully understood. This award supports the study of the strong force by probing the substructure of matter through experiments at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News, Virginia, and the Paul Scherrer Institute (PSI) in Switzerland. The research helps to address overarching questions about describing neutrons and protons in terms of their quark and gluon constituents, interactions that arise when two or three bodies are present in other media, the properties of dense nuclear matter, and the structure of nucleons. Answering these and related questions is a complex task that requires the dedicated experimental observations and careful testing of theoretical predictions against measured observations that are the goal of this project. This research will help discovery in and advance understanding of nuclear physics, and will promote teaching, training, and learning. The preparation of junior scientists plays a central role in the supported activities.The nuclear physics research program at the University of South Carolina (UofSC) is based at the Thomas Jefferson National Accelerator Facility (JLab) in Newport News, Virginia, and the Paul Scherrer Institute (PSI) in Switzerland. At PSI, the group is performing the MUSE experiment, which will address the proton-radius puzzle in simultaneous measurements of the electron-proton and muon-proton elastic cross sections with positively and negatively charged leptons. Each of the four sets of data will allow the extraction of the proton charge radius. In combination, the data test possible differences between the electron and muon interactions and additionally two-photon exchange effects. The group’s program at JLab will continue to provide crucial high precision, polarized and unpolarized observables that will address present problems in strong QCD. The elastic and transition form-factor will trace the evolution from meson baryon to dressed-quark degrees of freedom, establish the early onset of precocious scaling that further manifests the three-quark structure of baryons, and address the dynamical mass generation and confinement problem. The cross-sections for lambda deuteron elastic scattering will provide new and independent constraints on the two- and three-body hyperon-nucleon force, which is essential to understand the properties of neutron stars. The cross-sections for J/ψ photoproduction off the deuteron will give a direct estimate of the J/ψ-N cross-section and a very first glimpse into the gluon structure of deuterons. Completing meson-photoproduction measurements will settle in an almost model-independent way lingering problems in N* physics and verify the SU(6)×O(3)-predicted three-quark baryon structure. The properties of hadrons are modified in the medium and bound proton electromagnetic form factors may differ from those in the vacuum, as revealed for the first time by the group's earlier measurements. The experiments on nuclear targets at MAMI and JLab, respectively, will confirm or refute these results. The observations of such phenomena are potentially transformative in how we view hadrons and their interactions in nuclear matter.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.

虽然普通物质质量的98%是由于强亚原子力，但这种力的现有理论（量子色动力学）仍然没有完全理解。该奖项支持通过在弗吉尼亚州纽波特纽斯的托马斯杰斐逊国家加速器设施（JLab）和瑞士的保罗谢勒研究所（PSI）进行实验来探索物质的子结构，从而研究强作用力。 这项研究有助于解决关于描述中子和质子的夸克和胶子成分，当两个或三个物体存在于其他介质中时产生的相互作用，致密核物质的性质以及核子结构的首要问题。解决这些问题和相关问题是一项复杂的任务，需要专门的实验观察，并根据测量观察仔细测试理论预测，这是本项目的目标。这项研究将有助于发现和促进对核物理的理解，并将促进教学，培训和学习。南卡罗来纳州大学（UofSC）的核物理研究项目设在弗吉尼亚州纽波特纽斯的托马斯·杰斐逊国家加速器实验室（JLab）和瑞士的保罗·谢勒研究所（PSI）。在PSI，该小组正在进行MUSE实验，该实验将解决质子半径难题，同时测量带正电荷和负电荷的轻子的电子-质子和μ子-质子弹性截面。四组数据中的每一组都将允许提取质子电荷半径。结合起来，这些数据测试了电子和μ子相互作用以及双光子交换效应之间可能存在的差异。该小组在JLab的计划将继续提供至关重要的高精度，极化和非极化的观测，将解决强QCD目前的问题。弹性和跃迁形状因子将追踪从介子重子到缀饰夸克自由度的演化，建立早熟标度的早期开始，进一步表明重子的三夸克结构，并解决动力学质量产生和禁闭问题。λ氘弹性散射的截面将为二体和三体超子-核子力提供新的和独立的约束，这对理解中子星的性质至关重要。氘核光生J/N的截面将给出J/N-N截面的直接估计，并首次看到氘核的胶子结构。完成介子光生测量将以一种几乎与模型无关的方式解决N* 物理中悬而未决的问题，并验证SU（6）×O（3）预测的三夸克重子结构。强子的性质在介质中被修改，束缚质子的电磁形状因子可能与真空中的不同，这是该小组早期测量首次揭示的。MAMI和JLab的核靶实验将分别证实或反驳这些结果。对这些现象的观察可能会改变我们如何看待强子及其在核物质中的相互作用。该奖项反映了NSF的法定使命，并被认为值得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来支持。

项目成果

Observation of Correlations between Spin and Transverse Momenta in Back-to-Back Dihadron Production at CLAS12

CLAS12 背靠背双强子生产中自旋和横向动量之间相关性的观察

• DOI: 10.1103/physrevlett.130.022501
• 发表时间: 2023
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Avakian, H.;Hayward, T. B.;Kotzinian, A.;Armstrong, W. R.;Atac, H.;Ayerbe Gayoso, C.;Baashen, L.;Baltzell, N. A.;Barion, L.;Bashkanov, M.
• 通讯作者: Bashkanov, M.

12C(e,e'pN) measurements of short range correlations in the tensor-to-scalar interaction transition region

张量到标量相互作用过渡区域的短程相关性的 12C(e,epN) 测量

• DOI: 10.1016/j.physletb.2021.136523
• 发表时间: 2021
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: Korover, I.;Pybus, J.R.;Schmidt, A.;Hauenstein, F.;Duer, M.;Hen, O.;Piasetzky, E.;Weinstein, L.B.;Higinbotham, D.W.;Adhikari, S.
• 通讯作者: Adhikari, S.

Observation of large missing-momentum (e,e′p) cross-section scaling and the onset of correlated-pair dominance in nuclei

观察大缺失动量 (e,e-p) 横截面缩放和原子核中相关对优势的开始

• DOI: 10.1103/physrevc.107.l061301
• 发表时间: 2023
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: Korover, I.;Denniston, A. W.;Kiral, A.;Schmidt, A.;Lovato, A.;Rocco, N.;Nikolakopoulos, A.;Weinstein, L. B.;Piasetzky, E.;Hen, O.
• 通讯作者: Hen, O.

Alignment of the CLAS12 central hybrid tracker with a Kalman Filter

CLAS12 中央混合跟踪器与卡尔曼滤波器的对齐

• DOI: 10.1016/j.nima.2023.168032
• 发表时间: 2023
• 期刊: Detectors and Associated Equipment
• 作者: Paul, S.J.;Peck, A.;Arratia, M.;Gotra, Y.;Ziegler, V.;De Vita, R.;Bossù, F.;Defurne, M.;Atac, H.;Gayoso, C. Ayerbe
• 通讯作者: Gayoso, C. Ayerbe

First Measurement of Hard Exclusive π−Δ++ Electroproduction Beam-Spin Asymmetries off the Proton

首次测量质子外电产生束自旋不对称性

• DOI: 10.1103/physrevlett.131.021901
• 发表时间: 2023
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Diehl, S.;Trotta, N.;Joo, K.;Achenbach, P.;Akbar, Z.;Armstrong, W. R.;Atac, H.;Avakian, H.;Baashen, L.;Baltzell, N. A.
• 通讯作者: Baltzell, N. A.