Precision Ultra-High Energy Neutrino Astrophysics and New Signatures Enabled by a Complete Treatment of Birefringence in Antarctic Ice

精密超高能中微子天体物理学和通过彻底处理南极冰中双折射而实现的新特征

• 批准号: 2209588
• 负责人: Amy Connolly
• 金额: $ 38.5万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2209588&HistoricalAwards=false
• 关键词: Precision; Ultra; Energy; Neutrino; Astrophysics

Ultra-high energy (UHE) neutrinos with energies greater than 10^17 electronvolts are a key missing piece in the rapidly developing field of multi-messenger astrophysics. Their detection will prove essential in answering the century-old question of the nature of the most extreme astrophysical sources. Experiments employing radio techniques are amongst the most promising for measuring UHE neutrinos, where such event interactions occurring in natural ice environments result in detectable radio-frequency signals propagating over kilometer-scale distances. This award supports scientists at the Ohio State University performing research in the study of key ice parameters that directly impact the searches for the first detections of UHE neutrinos. The awarded program will leverage an interdisciplinary approach – spanning neutrino astrophysics, climate science, glaciology, remote sensing, evolutionary computation, and antenna engineering - to address the property of ice birefringence at the NSF’s Amundsen-Scott South Pole Station, Antarctica. Undergraduate researchers will play key roles in the interdisciplinary team, including leading the GENETIS project to assess the impact of birefringence on optimal designs of next-generation arrays for detecting UHE neutrinos. In addition, through the ASPIRE program, high school women will have the opportunity to gain first-hand research experiences. Quantifying the birefringence parameters (where the speed of a signal depends on its direction and polarization) in the ice is necessary to determine the local polarization where a radio signal is emitted in a neutrino interaction. A signal produced in the ice propagates as two rays that travel at different speeds. If the birefringence parameters are known, the time delay between the two rays would be a clear signature of a signal originating from within the ice, and provides a precise measure of the distance to the interaction necessary for the event energy reconstruction. Using pulser measurements taken with the deployed Askaryan Radio Array (ARA) at South Pole will provide the best fit depth-dependent parameters characterizing the ice birefringence. These parameters may then be incorporated into a complete ice model for detection of UHE neutrinos. Folding this information into the expected radio emission signatures will lower previous search thresholds and enhance the on-going search for the first detection of UHE neutrinos.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.

能量大于10^17电子伏特的超高能量（UHE）神经元是迅速发展的多通信天体物理学领域中的关键部分。他们的发现对于回答了多个世纪最极端的天体物理学来源的性质问题至关重要。采用无线电技术的实验是测量神经元的最有前途的实验之一，在自然冰环境中发生这种事件相互作用导致可检测到的射频信号在公里尺度距离内传播。该奖项支持俄亥俄州立大学的科学家进行研究，以研究关键的ICE参数，这些参数直接影响了对UHE神经元的首次检测的搜索。授予的计划将利用跨学科的方法 - 跨越神经元的天体物理学，气候科学，冰川学，遥感，进化计算和天线工程 - 在NSF的Amundsen -Scott South Pole station，Antarctica，NSF的Amundsen -Scott South Pole站。本科研究人员将在跨学科团队中扮演关键角色，包括领导Genetis项目，以评估双折射对检测UHE神经元的下一代阵列最佳设计的影响。此外，通过Aspire计划，高中妇女将有机会获得第一手研究经验。必须在冰中量化双折射参数（信号的速度取决于其方向和极化）对于确定在中性相互作用中发出无线电信号的局部极化。冰中产生的信号传播，因为两条射线以不同的速度传播。如果已知双折射参数，则两条光线之间的时间延迟将是源自冰内的信号的明确签名，并提供了对事件能量重建所需的相互作用的距离进行精确测量。使用在南极部署的Askaryan无线电阵列（ARA）进行的脉冲测量值将提供表征冰发双折射的最佳依赖深度依赖性参数。然后可以将这些参数纳入完整的ICE模型中以检测UHE神经元。将此信息折叠到预期的无线电排放签名中，将降低以前的搜索阈值，并增强对UHE Neuronos的首次检测的持续搜索。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优点和更广泛的影响来审查标准，通过评估来诚实地对支持进行评估。