Using IceCube to Search for Diffuse Neutrino Fluxes at Ultra-High Energies

在高能下，只有中微子可以直接从宇宙最遥远的地方或从最具灾难性、威力惊人的区域深处直接传递天体物理信息。中微子提供了自然如何加速粒子的独特视角，并可以澄清强子在天体物理环境中的作用。自2005年1月以来，IceCube已经部署了59个(80个)IceCube字符串，IceCube协作有望显著推动最先进的技术。该奖项将提供资金，通过开发和扩展数据分析和模拟工具，利用冰立方天文台搜索超高能(UHE)中微子的扩散通量，从而加快科学前沿的进展。拟议的工作将开发事件重建代码，并将研究通过利用完整波形记录中包含的信息来重建事件的新程序。他们提出的研究计划包括使用超级计算机集群对冰立方中的UHE中微子事件进行模拟研究，他们已经开始调查UHE能量下的性能。它们已被批准在TeraGrid集群上运行500,000个CPU小时。两年的IceCube数据应该会将电流通量限制提高4倍，因为UHE分析中几乎没有留下背景。如果没有发现信号，那么通量极限将小于任何版本的Waxman-Bahall界限，这意味着宇宙线加速器在产生中微子方面肯定效率较低。这项提议的更广泛的影响为研究生和博士后的好奇心和想象力驱动的研究提供了一个出口，他们将有机会学习数据采集电子学、探测器模拟和数据处理。学生培训是建立在强大的导师基础上的。

At high energies, only neutrinos can directly convey astrophysical information from the most distant reaches of the Universe or from deep inside the most cataclysmic, breathtakingly powerful, regions yet identified. Neutrinos provide a unique view of how nature accelerates particles and can clarify the role of hadrons in the astrophysical milieu. With 59 (out of 80) IceCube strings deployed since January 2005, the IceCube collaboration is poised to advance the state-of-the-art by a significant margin. This award will provide funds to accelerate the advance of the scientific frontier by developing and extending data analysis and simulation tools to search for a diffuse flux of Ultra-High Energy (UHE) neutrinos using the IceCube Observatory. The proposed work will develop event reconstruction code and will investigate new procedures to reconstruct events by taking advantage of the information contained within the complete waveform record. Their proposed research plan includes simulation studies of UHE neutrino events in IceCube using a supercomputer cluster and they have started to investigate the performance at UHE energies. They have been approved for 500,000 cpu hours on the Teragrid clusters. Two years of IceCube data should improve current flux limits by a factor of 4 since little background remains in the UHE analysis. If no signal is found, then the flux limits will be less than any version of the Waxman-Bahcall bound, which implies that cosmic ray accelerators must be less efficient at producing neutrinos. The broader impacts of this proposal provide an outlet for curiosity and imagination driven research by graduate and postdoctoral students who will be given the opportunity to learn about data acquisition electronics, detector simulation, and data processing. Student training is founded on strong mentorship.