Cascade-based Search for Tau Neutrinos in IceCube Data

最近建成的冰立方中微子观测站，位于地理南极附近，正在收集所有中微子探测器中仪器体积最大的物理数据。完整的冰立方探测器测量了一整立方公里的冰，包括探测器中心密集分布的“深核”组件。冰立方在所有探测器中对TeV - PeV能量的天体物理中微子具有最高的灵敏度。DeepCore将冰立方的探测范围扩展到接近10 GeV的能量，冰立方的大型大气中微子样本是对现有长基线加速器中微子实验的补充。未来三年将看到冰立方完整数据集的开发，为中微子物理学和天体物理学提供丰富的可能性。该奖项将继续支持阿拉巴马大学（UA）的冰立方分析小组在tau中微子通道中探索基于级联的中微子搜索。在高能量下，tau通道不受大气中微子背景的影响，这使得tau中微子探测成为天体物理源的“确凿证据”。UA小组将专注于将级联优越的能量分辨率与独特的波形和改进的tau中微子的方向分辨率结合起来。DeepCore将加强对能量低至100 TeV的天体物理学tau中微子的搜索，在那里，通量预计会更高，中微子可以从天空的两个半球观测到。在25 GeV左右的低能处，大气中微子振荡产生的tau中微子出现概率最大，UA小组将改进级联重建算法的方向和能量分辨率，以便在DeepCore中搜索tau中微子级联的出现。更广泛的影响：阿拉巴马大学位于多元化的塔斯卡卢萨社区，大学对本科和跨学科研究有着坚定的承诺。PI为高中生开发了一个基于扩散云室的活动，并通过UA的Science in Motion项目向当地的物理和化学高中教师展示了这个活动。pi将继续与ASIM合作，将高能物理活动带入高中课堂。亚利桑那大学物理与天文系有一个强大的公共宣传计划，pi将继续在塔斯卡卢萨和伯明翰的亚利桑那大学校园进行公共宣传活动。

The recently completed IceCube neutrino observatory, located near the geographic South Pole, is collecting physics data in the largest instrumented volume of any neutrino detector. The complete IceCube detector instruments a full cubic kilometer of ice, including a densely spaced "DeepCore" component at the center of the detector. IceCube has the greatest sensitivity of any detector to astrophysical neutrinos at TeV - PeV energies. DeepCore extends IceCube's range to energies near 10 GeV where IceCube's large sample of atmospheric neutrinos is complementary to existing long baseline accelerator neutrino experiments. The next three years will see the exploitation of the full dataset of IceCube, with rich possibilities for neutrino physics and astrophysics.This award continues support for the IceCube analysis group at the University of Alabama (UA) to explore cascade-based neutrino searches in the tau neutrino channel. At high energies, the tau channel is free of atmospheric neutrino background, making tau neutrino detection a "smoking gun" for an astrophysical source. The UA group will focus on combining the superior energy resolution of cascades with the unique waveforms and improved direction resolution of tau neutrinos. DeepCore will enhance the search for astrophysical tau neutrinos at energies down to 100 TeV where fluxes are expected to be higher and neutrinos can be observed from both hemispheres of the sky. At low energies around 25 GeV, where the tau neutrino appearance probability from atmospheric neutrino oscillation is maximal, the UA group will improve the directional and energy resolution of cascade reconstruction algorithms in order to search for the appearance of tau neutrino cascades in DeepCore.Broader Impact: The University of Alabama is located in the diverse community of Tuscaloosa, and the university has a strong commitment to undergraduate and interdisciplinary research. The PI has developed an activity for high school students based on diffusion cloud chambers and has presented this activity to local physics and chemistry high school teachers through the UA Science in Motion Program. The PIs will continue to work with ASIM to bring high energy physics activities to the high school classroom. The UA Department of Physics and Astronomy has a strong public outreach program, and the PIs will continue public outreach activities at the UA campuses in Tuscaloosa and Birmingham.