冰立方中微子天文台对非标准中微子振荡的搜寻
Searches for Non-Standard Neutrino Oscillations with the IceCube Neutrino Observatory
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中文总结 AI 辅助
利用冰立方10.67年大气中微子数据搜寻不稳定惰性中微子模型，排除大部分短基线反常偏好参数空间，并发展未来反中微子搜寻技术。
中文摘要 AI 辅助
LSND、MiniBooNE和镓实验观测到的短基线中微子反常现象，可以通过在太阳、大气和反应堆振荡测量所确定的三种中微子态之外增加额外中微子态来解释。将这些反常现象参数化的最小3+1惰性中微子模型，与其他振荡实验的零结果及宇宙学约束存在显著矛盾，这促使人们探索非最小扩展模型，其中额外的质量本征态是不稳定的。本论文利用冰立方中微子天文台10.67年的高能大气中微子数据，搜寻一种不稳定的惰性中微子模型，在该模型中，重质量本征态ν4衰变为两个不可见粒子。分析发现，相对于无衰变的3+1假设，数据不偏好惰性衰变，并在90%置信水平上排除了全局拟合短基线数据所偏好的大部分参数空间，从而对这一反常现象的非最小解释提供了强约束。论文还为进一步针对反中微子共振消失的冰立方惰性中微子搜寻奠定了基础。论文包含三项贡献：对中微子-核子及中微子-核深非弹性散射截面的全面计算、新的机器学习重建技术，以及信号效率为先前版本两倍的改进事件选择。这些工具共同实现了中微子与反中微子的统计分离，并为冰立方下一代惰性中微子搜寻建立了基础设施。
英文摘要
The short-baseline neutrino anomalies observed by LSND, MiniBooNE, and the gallium experiments can be explained by additional neutrino states beyond the three established by solar, atmospheric, and reactor oscillation measurements. The minimal 3+1 sterile neutrino model that parameterizes these anomalies is in significant tension with null results from other oscillation experiments and with cosmological constraints, motivating the exploration of non-minimal extensions in which the additional mass eigenstate is unstable. This thesis presents a search for an unstable sterile neutrino model, in which the heavy mass eigenstate $ν_4$ decays to two invisible particles, using 10.67 years of high-energy atmospheric neutrino data from the IceCube Neutrino Observatory. The analysis finds no preference for sterile decay over the no-decay 3+1 hypothesis and excludes most of the parameter space preferred by global fits to short-baseline data at 90% confidence level, providing a strong constraint on this non-minimal explanation of the anomalies. The thesis additionally develops the foundation for a future sterile neutrino search at IceCube targeting the resonant disappearance of antineutrinos. Three contributions are presented: a comprehensive calculation of neutrino-nucleon and neutrino-nucleus deep-inelastic scattering cross sections, new machine-learning reconstruction techniques, and an improved event selection with twice the signal efficiency of the previous iteration. Together, these tools enable statistical separation of neutrinos and antineutrinos and establish the infrastructure for the next generation of sterile neutrino searches with IceCube.
发表机构
- Department of Physics（物理系）
- Drexel University（德雷塞尔大学）
机构由 AI 辅助整理，请以论文原文为准。
