RII-Track 4: Hidden Sectors at the Fermilab Short-Baseline Neutrino Program

费米实验室目前和即将进行的实验正在确立美国在中微子研究方面的世界领先地位。中微子是目前已知的最不为人所知的基本粒子。中微子探测器非常灵敏，因为它们被设计成探测中微子与物质碰撞所引起的微小能量沉积。由于这种灵敏度，这些探测器可以用来搜索中微子以外的粒子。例如，关于暗物质的多种理论，即我们宇宙中未知的额外质量，预测了可以通过费米实验室中微子设施产生和观察到的新粒子。该项目启动了俄克拉荷马州立大学和费米实验室研究人员之间的合作，以研究中微子探测器作为新粒子探测器的应用。目标是发展对粒子物理标准模型之外的理论的搜索，这是我们目前在亚原子水平上对自然的最好理解。与拥有中微子物理专业知识的费米实验室物理学家合作，将使俄克拉荷马州的研究人员详细了解世界级粒子物理实验，最终使他们能够在中微子计划持续到本世纪30年代时为费米实验室的研究做出贡献。通过建立粒子物理的研究能力，这项工作将长期加强俄克拉荷马州的STEM研究和教育。这项奖学金支持PI和一名研究生访问费米实验室，以开发使用短基线中微子(SBN)计划和深层地下中微子实验(DUNE)探测器的独特计时能力来搜索新的光、弱耦合状态的技术。PI和学生将与费米实验室理论物理系的东道主科学家合作，进行现象学研究，应用这些探测器的纳秒级分辨率来分离某些隐藏扇区模型的特征。这项研究有两个具体目标。第一个目标是计算费米实验室中微子实验对亚GeV暗物质在原子核上散射的灵敏度。参与者将构建结合时间和运动学切割的分析，以区分暗物质散射和中微子诱导的背景。计时技术的使用预计将允许在不需要专门的磨合光束倾倒模式的情况下搜索浅暗物质，这样就可以同时研究暗物质和中微子在原子核上的散射。第二个目标是量化费米实验室中微子设施的隐蔽扇区范围，这些中微子和介子被阻止在探测器设备中，随后在静止时衰变。预计这些粒子的衰变产物将具有明显的方向性和时序性。参与者将模拟停止的介子和介子的衰变产生隐藏的扇区介体。特别是，他们将开发对Numi吸收体中产生的新粒子的搜索，这些新粒子到达SBN探测器的时间比通常的中微子散射信号要晚。这一裁决反映了NSF的法定任务，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。

Current and upcoming experiments at Fermilab are establishing the United States as the world leader in the study of neutrinos, the least well understood fundamental particles known today. Neutrino detectors are very sensitive as they are designed to detect minute depositions of energy caused by collisions of neutrinos with matter. Because of this sensitivity, these detectors can be used to search for particles other than neutrinos. For instance, multiple theories of dark matter, the unknown extra mass in our universe, predict new particles that could be produced and observed with the Fermilab neutrino facilities. This project initiates a collaboration between researchers at Oklahoma State University and Fermilab to investigate such applications of neutrino detectors as probes of new particles. The goal is to develop searches for theories beyond the Standard Model of particle physics, our current best understanding of nature at a subatomic level. Collaboration with Fermilab physicists with expertise in neutrino physics will give Oklahoma researchers a detailed understanding of world-class particle physics experiments, ultimately allowing them to contribute to studies at Fermilab as the neutrino program continues through the 2030s. By building research capacity in particle physics, the work will enhance STEM research and education in Oklahoma over the long term.This fellowship supports the visits of the PI and a graduate student to Fermilab to develop techniques to search for new light, weakly coupled states using the unique timing capabilities of the Short-Baseline Neutrino (SBN) program and Deep Underground Neutrino Experiment (DUNE) detectors. The PI and student will collaborate with host scientists in the Fermilab Theoretical Physics Department, performing phenomenological studies that apply the nanosecond-scale resolution of these detectors to isolate signatures of certain hidden sector models. The research has two specific objectives. The first objective is to compute the sensitivities of Fermilab neutrino experiments to sub-GeV dark matter scattering off nuclei. The participants will construct analyses that combine timing and kinematic cuts to discriminate dark matter scattering from neutrino-induced backgrounds. The use of timing is expected to allow for light dark matter searches without the need for a dedicated run-in beam dump mode, so that dark matter and neutrino scattering off nuclei can be studied simultaneously. The second objective is to quantify the hidden sector reach of the Fermilab neutrino facilities from pions and muons that are stopped in the detector apparatus and subsequently decay at rest. The decay products of these particles are expected to have distinct directional and timing properties. The participants will simulate the production of hidden sector mediators from the decays of stopped pions and muons. In particular, they will develop searches for new particles produced in the NuMI absorber whose arrival in the SBN detectors is delayed relative to the usual neutrino scattering signal.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.