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

在高能量下，只有中微子可以直接传递来自宇宙最遥远的地方的天体物理信息，或者来自最具灾难性、最令人惊叹的强大区域的深处。中微子提供了自然界如何加速粒子的独特视角，并可以阐明强子在天体物理环境中的作用。自2005年1月以来，80个冰立方柱中有59个已经投入使用，冰立方合作项目已经准备好将最先进的技术大大提高。该奖项将提供资金，通过开发和扩展数据分析和模拟工具，加速科学前沿的发展，利用冰立方天文台寻找超高能量（UHE）中微子的漫射通量。拟议的工作将开发事件重建代码，并将研究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，他们已经开始研究UHE能量下的性能。他们已经被批准在Teragrid集群上使用500000 cpu小时。冰立方两年的数据将使当前的通量限制提高4倍，因为在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-Bahcall边界，这意味着宇宙射线加速器产生中微子的效率一定较低。该提案的广泛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。学生培训建立在强有力的指导基础上。

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.