RUI: Studying the Strong Nuclear Force at Augustana University

这个奖项继续了南达科他州苏福尔斯奥古斯塔纳大学研究强核力的科学项目。强核力是由一种叫做胶子的粒子携带的，胶子将质子和中子结合在一起，在每个原子的核心形成一个原子核。因为原子构成了可观测物质的大部分，所以了解原子核内胶子的数量及其运动对于从基本层面理解物质是必要的。奥古斯塔纳的核物理小组通过分析布鲁克海文国家实验室的相对论重离子对撞机（RHIC）产生的高能核碰撞来研究原子核的胶子含量。该小组将分析由PHENIX探测器测量的氘与金碰撞的数据。该小组还将参与建造和安装新的sPHENIX探测器，这是下一代探测器，将在大约2023年开始测量RHIC碰撞的结果。这个强核物理的项目是南达科他州唯一的一个。它为国家和地区的人们提供了学习和参与这种物理学的机会。该提案将支持学习物理或预科工程的本科生。对学生的教育好处是广泛的。学生将获得实用技能，如计算机编程、大数据集分析、电气工程应用和机械工程设计。这些技能可以转移到学生、州和国家感兴趣的其他职业中。学生将参加每周的合作会议，出席国家会议，并参观合作机构。这样的机会将培养他们的沟通技巧，扩大他们的专业网络，使他们与潜在的研究生院接触，并为21世纪的技术工作做好准备。在强物理中，一个突出的实验问题是测量低动量分数x下胶子的核部分子分布函数。该奖项继续了PI和本科生从两方面研究这一领域的工作。首先，完成2016年RHIC PHENIX实验记录的200 GeV中速下d + Au π -强子方位相关测量并发表。分析将使用μ子活塞量热计（MPC）和μ子活塞量热计扩展（MPC- ex）。MPC是一种PbWO4晶体电磁量热计。MPC-EX是一种具有高分割的Si-W预淋浴探测器，可以从e80 GeV的pi- 0衰变中分离光子。使用不同伪快度的粒子对，包括非常正的MPC+MPC- ex区域，将测量成对伪快度的函数对速率和方位相关形状。这些测量结果将有助于了解核中低x胶子的运动学，并允许进行饱和物理或冷核物质能量损失的测试。其次，该小组正在从PHENIX过渡到sPHENIX，这是下一代重离子探测器，将利用高亮度RHIC运行来测量射流和重味物理。该小组将在2021年和2022年夏季花费大量时间帮助在相互作用区域建造组件并安装探测器。第一批数据预计将于2023年初公布。该小组将专注于利用双粒子相关性测量低能喷流。未来，sPHENIX探测器预计将在2020年后期在布鲁克海文建造的电子-离子对撞机（EIC）转变为Day-1物理探测器。EIC的主要物理驱动是测量原子核的胶子含量。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

This award continues the scientific program to study the strong nuclear force at Augustana University in Sioux Falls, South Dakota. The strong nuclear force is carried by particles called gluons that bind protons and neutrons together to form a nucleus at the core of every atom. Because atoms make up the majority of the observable matter, knowing the number of gluons inside a nucleus and their motion is necessary to understand matter at its fundamental level. The nuclear physics group at Augustana studies the gluon content of the nucleus by analyzing high energy nuclear collisions produced at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The group will analyze data from deuterium + gold collisions measured with the PHENIX detector. The group will also participate in the building and installing the new sPHENIX detector, a next-generation detector that will measure results from collisions at RHIC beginning in approximately 2023. This program in strong nuclear physics is the only one of its kind in South Dakota. It provides those in the state and the region opportunities to study and participate in this physics. The proposal will support undergraduates studying physics or pre-engineering. The educational benefits for the students are broad. Students will gain practical skills such as computer programming, analysis of large data sets, electrical engineering application, and mechanical engineering design. These skills are transferable to other vocations of interest to the student, the state, and the nation. Students will participate in weekly collaboration meetings, present at national conferences, and visit collaborating institutions. Such opportunities will build their communication skills, grow their professional network, put them in contact with potential graduate schools, and prepare them for 21st-century technical jobs. An outstanding experimental question in strong-force physics is measuring the nuclear parton distribution function of gluons at low momentum fraction x. This award continues work by the PI and undergraduates to study this area in two ways. First, the measurement of pi0-hadron azimuthal correlations in d + Au at midrapidity of 200 GeV recorded by the PHENIX experiment at RHIC in 2016 will be completed and published. The analysis will utilize the Muon Piston Calorimeter (MPC) and the Muon Piston Calorimeter Extension (MPC-EX). The MPC is a PbWO4 crystal electromagnetic calorimeter. The MPC-EX is a Si-W pre-shower detector with high segmentation that can separate photons from pi-zero decays for E 80 GeV. Using pairs of particles in different pseudorapidity, including the very forward MPC+MPC-EX region, the pair rate and azimuthal correlation shapes will be measured as a function of pair pseudorapidity. These measurements should yield insights to the kinematics of low-x gluons in the nucleus and allow tests of saturation physics or cold nuclear matter energy loss. Second, the group is transitioning from PHENIX to sPHENIX, a next-generation heavy ion detector that will take advantage of high-luminosity RHIC running to measure jets and heavy flavor physics. The group will spend significant time during the summers of 2021 and 2022 helping to build components and install the detector at the interaction region. First data is expected in early 2023. The group will focus on measurements of low-energy jets using two-particle correlations. In the future, the sPHENIX detector is expected to transform into a Day-1 physics detector the Electron-Ion Collider (EIC) that will be built at Brookhaven in the later 2020's. The main physics driver for the EIC is to measure the gluon content of the nucleus.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.