RUI: Probing the Structure of Nucleons in Omega Meson Electroproduction

RUI：探索欧米茄介子电生产中的核子结构

• 批准号: 2012826
• 负责人: Philip Cole
• 金额: $ 22.5万
• 依托单位: Lamar University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2012826&HistoricalAwards=false
• 关键词: RUI; Probing; Structure; Nucleons; Omega

Understanding exactly how the strong force is generated inside the nucleus is one of the greatest intellectual challenges facing nuclear physicists today. The strong force gives rise to the nuclear forces that bind protons and neutrons together inside the nucleus. The strong force is mediated by the exchange of particles known as gluons. It is this gluon interaction that accounts for most of mass of the nucleon. The nucleon is the general term for either a proton or a neutron. Nucleons are formed of three valence quarks embedded in a frothing sea of gluons. Our knowledge of how protons and neutrons are constructed from their quark and gluon constituents, however, is rudimentary at best. An energetic particle, such as an electron, incident on a nucleon can interact directly with one of the valence quarks inside, causing the quark to undergo a flip in spin or endowing the quark with an orbital or radial excitation. With a quark in a higher energy state, the excited nucleon becomes more massive. These excited states are called nucleon resonances (N*s) and exist for the briefest of moments – on the order of a trillionth of a trillionth of a second (10−24 s), and thence will decay into other particles. The types of particles produced and how they are distributed in space provides key information on the make-up of the proton. Lamar University is a Primarily Undergraduate Institution. Over the course of the past two decades, the PI has established a strong record of involving undergraduate students in his research program, and that practice will continue with support from this award. These fundamental measurements on understanding nucleon resonances at Jefferson Lab (Newport News, Virginia) and at ELSA (Bonn, Germany), along with the strong educational focus of this award, are in keeping with the key objectives of the Nuclear Science Advisory Committee’s 2015 Long-Range Plan and thereby serve the national interest.This research program is a study of the fundamental properties and structure of nucleons by using a beam of linearly-polarized photons and/or polarized electrons at Jefferson Lab and at ELSA. The strong nuclear interaction is responsible for phenomena over a large distance scale from the binding of quarks by gluons, the combinations of quarks into colorless hadrons, the binding of nucleons into nuclei, and the collective behavior of large nuclei. This research group seeks answers to questions such as how valence quarks self-assemble when sea quark and gluon contributions are minimal, the nature of how gluons attach to quarks to increase the mass of current quarks to that of constituent quarks, and how quarks resonate inside the nucleon to form excited assemblies of quarks. The PI and his group of undergraduate students aim to understand the emergent behavior and structure from assemblies of quarks and gluons. The probe for these studies will be the omega meson. There is great discovery potential in probing the structure of N*s through the clean and unambiguous signal of the omega meson. Moreover, there is a significant dearth of data of baryon resonances decaying through the omega mode as a function of momentum transfer.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.

准确理解强力是如何在原子核内部产生的，是当今核物理学家面临的最大智力挑战之一。这种强力产生了核力，它将质子和中子在原子核内束缚在一起。 这种强力是由称为胶子的粒子的交换所介导的。正是这种胶子相互作用占了核子质量的大部分。核子是质子或中子的总称。 核子是由三个价夸克嵌入在一个充满泡沫的胶子海洋中形成的。然而，我们对质子和中子是如何由夸克和胶子组成的知识，充其量也只是初步的。一个高能粒子，例如电子，入射到核子上，可以直接与核子内部的一个价夸克相互作用，导致夸克经历自旋翻转，或者赋予夸克轨道或径向激发。当夸克处于更高的能量状态时，激发的核子变得更大。这些激发态被称为核子共振（N*s），存在的时间最短--大约为万亿分之一秒（10−24 s），然后衰变为其他粒子。 产生的粒子类型以及它们在空间中的分布方式提供了有关质子组成的关键信息。 拉马尔大学是一所私立本科院校。 在过去的二十年中，PI已经建立了一个强大的记录，让本科生参与他的研究计划，这种做法将继续得到这个奖项的支持。 杰斐逊实验室的这些理解核子共振的基本测量（弗吉尼亚州纽波特纽斯）和艾尔莎（德国波恩），沿着这一奖项强烈的教育重点，符合核科学咨询委员会2015年长期目标的关键目标，这一研究计划是利用原子核物理学的方法，研究核子的基本性质和结构，在杰斐逊实验室和艾尔莎的线性极化光子和/或极化电子束。强核相互作用是导致从夸克与胶子的结合、夸克与无色强子的结合、核子与核的结合以及大核的集体行为等大距离尺度现象的原因。这个研究小组寻求问题的答案，例如当海夸克和胶子贡献最小时，价夸克如何自组装，胶子如何附着在夸克上以增加当前夸克的质量到组分夸克的质量的性质，以及夸克如何在核子内共振以形成夸克的激发组件。 PI和他的本科生小组旨在了解夸克和胶子集合的涌现行为和结构。 这些研究的探针将是欧米茄介子。通过清晰明确的Ω介子信号来探测N*s的结构具有很大的发现潜力。此外，有一个显着缺乏的重子共振衰减通过欧米茄模式作为一个功能的动量transfer.This奖项反映了NSF的法定使命的数据，并已被认为是值得的支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。

项目成果

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.

$$K^{+}\Lambda $$ photoproduction at forward angles and low momentum transfer

$$K^{ }Lambda $$ 向前角度和低动量传递的照片制作

• DOI: 10.1140/epja/s10050-021-00392-0
• 发表时间: 2021
• 期刊: The European Physical Journal A
• 作者: Alef, S.;Bauer, P.;Bayadilov, D.;Beck, R.;Bella, A.;Bieling, J.;Braghieri, A.;Cole, P. L.;Elsner, D.;Di Salvo, R.
• 通讯作者: Di Salvo, R.

Performance of BDX-MINI veto systems

BDX-MINI 否决系统的性能

• DOI: 10.1016/j.nima.2022.167949
• 发表时间: 2023
• 期刊: Detectors and Associated Equipment
• 作者: Spreafico, M.;Battaglieri, M.;Bondí, M.;Celentano, A.;Cole, P.L.;De Napoli, M.;De Vita, R.;Marsicano, L.;Randazzo, N.;Smith, E.S.
• 通讯作者: Smith, E.S.

A multidimensional study of the structure function ratio σLT′/σ0 from hard exclusive π+ electro-production off protons in the GPD regime

GPD 体系中质子硬排他电生产结构函数比 LT-2/δ0 的多维研究

• DOI: 10.1016/j.physletb.2023.137761
• 发表时间: 2023
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: Diehl, S.;Kim, A.;Joo, K.;Achenbach, P.;Akbar, Z.;Amaryan, M.J.;Atac, H.;Avagyan, H.;Ayerbe Gayoso, C.;Baashen, L.
• 通讯作者: Baashen, L.

Electron-beam energy reconstruction for neutrino oscillation measurements.

用于中微子振荡测量的电子束能量重建。

• DOI: 10.1038/s41586-021-04046-5
• 发表时间: 2021
• 期刊: Nature
• 影响因子: 64.8
• 作者: Khachatryan M