Neutrino physics with JUNO
Neutrino physics with JUNO
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JUNO 的中微子物理
DOI：
10.1088/0954-3899/43/3/030401
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发表时间：
2016-03-01
影响因子：
3.5
通讯作者：
Zou, Jiaheng
中科院分区：
文献类型：
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作者：
An, Fengpeng;An, Guangpeng;Zou, Jiaheng
江门地下中微子观测站（JUNO）是一个20 kton多用途的地下液体闪烁探测器，其主要物理目标是确定中微子质量等级（MH）。JUNO探测器出色的能量分辨率和大的基准体积为解决中微子和天体粒子物理学中的许多重要课题提供了令人兴奋的机会。在本文件中，我们提出的物理动机和预期性能的JUNO探测器的各种建议的测量。介绍了中微子物理学的现状和存在的问题，讨论了JUNO运行6年后，如何通过对核电站群产生的反中微子的探测，确定中微子MH的3-4 σ意义。具有良好能量分辨率的反中微子谱的测量也将导致中微子振荡参数sin（2）theta（12），Delta m（21）（2）和垂直棒Delta m（ee）（2）垂直棒的精确测定，精度优于1%，这将在未来的MNSP矩阵的幺正性测试中发挥至关重要的作用。JUNO探测器不仅能够观测到来自发电厂的反中微子，还能够观测到来自地球和地外源的中微子/反中微子，包括超新星爆发中微子、弥散超新星中微子背景、地中微子、大气中微子和太阳中微子。由于JUNO的大尺寸，出色的能量分辨率和顶点重建能力，可以收集有关这些主题的有趣的新数据。例如，一个典型的核心坍缩超新星在10 kpc距离的中微子爆发将导致类似于5000个逆β衰变事件和类似于JUNO的2000个全味中微子-质子ES事件，这对于理解超新星爆炸的机制和探索新的现象，如集体中微子振荡至关重要。JUNO探测可见宇宙中所有过去核心坍缩超新星爆炸产生的中微子，将进一步提供有关宇宙恒星形成速率和平均核心坍缩中微子能谱的宝贵信息。在JUNO中可以检测到源自地球中铀和钍的放射性衰变的反中微子，其速度接近每年400次，大大改善了现有地球中微子事件样本的统计数据。JUNO收集的大气中微子事件可以为确定MH和θ（23）混合角的八分圆提供独立的输入。在JUNO探测到Be-7和B-8太阳中微子事件将为太阳金属丰度问题提供新的线索，并研究真空和物质主导的中微子振荡之间的过渡区。在轻不育中微子方面，通过对反应堆反中微子能谱的精确测量，可以识别出10-（5）eV（2）<Δ m（41）（2）< 10（-2）和足够大的混合角θ（14）的不育中微子。同时，JUNO还可以为我们提供极好的机会来验证eV尺度的无菌中微子假设，无论是使用放射性中微子源还是回旋加速器产生的中微子束。JUNO探测器还对其他几个超标准模型物理学敏感，例如通过p -> K++衰变通道寻找质子衰变，寻找太阳中暗物质湮灭产生的中微子，通过反应堆中微子事件率的恒星调制寻找洛伦兹不变性的破坏，以及寻找非标准相互作用的影响。拟议建造的JUNO探测器将提供一个独特的设施，以及时和具有成本效益的方式解决粒子和天体物理学中许多悬而未决的关键问题。它具有巨大的潜力，可以进一步推动我们对中微子基本性质的理解，中微子是我们宇宙的基石之一。
The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multipurpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy (MH) as a primary physics goal. The excellent energy resolution and the large fiducial volume anticipated for the JUNO detector offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. In this document, we present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. Following an introduction summarizing the current status and open issues in neutrino physics, we discuss how the detection of antineutrinos generated by a cluster of nuclear power plants allows the determination of the neutrino MH at a 3-4 sigma significance with six years of running of JUNO. The measurement of antineutrino spectrum with excellent energy resolution will also lead to the precise determination of the neutrino oscillation parameters sin(2) theta(12), Delta m(21)(2), and vertical bar Delta m(ee)(2)vertical bar to an accuracy of better than 1%, which will play a crucial role in the future unitarity test of the MNSP matrix. The JUNO detector is capable of observing not only antineutrinos from the power plants, but also neutrinos/antineutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, and solar neutrinos. As a result of JUNO's large size, excellent energy resolution, and vertex reconstruction capability, interesting new data on these topics can be collected. For example, a neutrino burst from a typical core-collapse supernova at a distance of 10 kpc would lead to similar to 5000 inverse-beta-decay events and similar to 2000 all-flavor neutrino-proton ES events in JUNO, which are of crucial importance for understanding the mechanism of supernova explosion and for exploring novel phenomena such as collective neutrino oscillations. Detection of neutrinos from all past core-collapse supernova explosions in the visible universe with JUNO would further provide valuable information on the cosmic star-formation rate and the average core-collapse neutrino energy spectrum. Antineutrinos originating from the radioactive decay of uranium and thorium in the Earth can be detected in JUNO with a rate of similar to 400 events per year, significantly improving the statistics of existing geoneutrino event samples. Atmospheric neutrino events collected in JUNO can provide independent inputs for determining the MH and the octant of the theta(23) mixing angle. Detection of the Be-7 and B-8 solar neutrino events at JUNO would shed new light on the solar metallicity problem and examine the transition region between the vacuum and matter dominated neutrino oscillations. Regarding light sterile neutrino topics, sterile neutrinos with 10-(5) eV(2) < Delta m(41)(2) < 10(-2) and a sufficiently large mixing angle theta(14) could be identified through a precise measurement of the reactor antineutrino energy spectrum. Meanwhile, JUNO can also provide us excellent opportunities to test the eV-scale sterile neutrino hypothesis, using either the radioactive neutrino sources or a cyclotron-produced neutrino beam. The JUNO detector is also sensitive to several other beyondthe-standard-model physics.Examples include the search for proton decay via the p -> K++ decay channel, search for neutrinos resulting from dark-matter annihilation in the Sun, search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate, and search for the effects of non-standard interactions. The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one of the building blocks of our Universe.