Determination of the Leptonic Mixing Angle Theta-13 with the Double Chooz Experiment

双Chooz实验的主要目的是测量反电子中微子的风味振荡。实验装置由两个几乎相同的探测器组成，它们测量距离法国Chooz核电站两个反应堆堆芯不同距离处的反电子中微子的通量。该实验对测量与轻子混合角Theta-13相关的反应堆中微子的消失进行了优化，但它对与假设的无菌中微子相关的附加振荡模式也很敏感。双Chooz合作成功地开创了使用相同的近距离和远距离探测器的实验概念，最大限度地减少了系统的不确定性。2006年该项目刚开始的时候，还不清楚效果是否存在，是否可以测量。同时，Theta-13是相对误差最小的中微子混合角，也是由于Double Chooz的结果。双Chooz的一个远探测器于2011年开始运行，第二个近探测器已于2015年初投入使用，实验在其全配置下运行至2018年。我们亚琛工业大学的团队自2007年以来一直得到DFG的资助。我们对“双Chooz”的建设和运行，以及数据分析，特别是之前对Theta-13的测量做出了重大贡献。我们已经为两个内部探测器提供了大约15%的光电倍增管，并开发了触发系统和数据采集系统的附加组件，该系统在探测器运行的所有阶段都以100%的效率非常可靠地工作。实验数据的分析仍在进行中。这项提议的目标是为Theta-13的测量提供一个最终结果，同时也为寻找惰性中微子提供一个最终结果。Theta-13的测定最终将受到系统不确定性的限制，因此我们的目标是使最终结果的这些误差最小化。双Chooz实验在这个方向上有几个独特的优势：两个探测器的位置使得两个反应堆对两个探测器的相对通量贡献是相似的。此外，在反应堆停止的阶段，背景可以精确测量。因此，我们期望Double Chooz的结果将在许多年内对Theta-13值的全球知识做出重大贡献。Theta-13的不确定度对中微子振荡领域至关重要，因为它是其他测量的输入，如中微子质量层次的测量、轻子扇区中的CP违和和PMNS矩阵的一致性测试。

The main goal of the Double Chooz experiment is the measurement of flavor oscillations of anti-electron neutrinos. The experimental setup consists of two nearly identical detectors that measure the flux of anti-electron neutrinos at different distances from the two reactor cores at the Chooz nuclear power plant in France. The experiment is optimized for measuring the disappearance of reactor neutrinos related to the leptonic mixing angle Theta-13 but it is also sensitive to additional oscillation modes related to hypothetical sterile neutrinos. The Double Chooz collaboration has successfully pioneered the experimental concept of using identical near and far detectors minimizing systematic uncertainties. Upon start of the project in 2006, it was unclear, if the effect existed and could be measured. Meanwhile Theta-13 is the neutrino mixing angle that has been measured with the smallest relative error, also because of results from Double Chooz. With one far detector, Double Chooz started operation in 2011, The second, near, detector of Double Chooz has been commissioned early 2015 and the experiment operated in its full configuration until 2018. Our group at RWTH Aachen has been funded by the DFG since 2007. We have significantly contributed to the construction and operation of Double Chooz, and to the data analysis, particularly the previous measurements of Theta-13. We have provided about 15% of the photomultipliers of both inner detectors and have developed the trigger system and additional components of the data acquisition system, which has been working very reliably at essentially 100% efficiency during all phases of detector operation. The analysis of the experimental data is still ongoing. Goal of this proposal is the production of a final result for the measurement of Theta-13, and additionally a final result for the search for sterile neutrinos. The determination of Theta-13 will be ultimately limited by systematic uncertainties and thus we are aiming for minimizing these errors for the final result. The Double Chooz experiment has several unique advantages in this direction: The two detectors are positioned such that the relative flux contribution from the two reactors is similar for both detectors. Furthermore, during phases when reactors are stopped, backgrounds can be precisely measured. Therefore, we expect that the result of Double Chooz will significantly contribute to the global knowledge of the value Theta-13 for many years. The uncertainty of Theta-13 is of critical importance to the field of neutrino oscillations, because it is an input to other measurements such as the measurement of the neutrino mass hierarchy, CP violation in the lepton sector and tests of the unitarity of the PMNS matrix.