在RENO实验中对能量和基线依赖的反应堆反中微子消失的观测。
Observation of Energy and Baseline Dependent Reactor Antineutrino Disappearance in the RENO Experiment.
作者信息
Choi J H, Choi W Q, Choi Y, Jang H I, Jang J S, Jeon E J, Joo K K, Kim B R, Kim H S, Kim J Y, Kim S B, Kim S Y, Kim W, Kim Y D, Ko Y, Lee D H, Lim I T, Pac M Y, Park I G, Park J S, Park R G, Seo H, Seo S H, Seon Y G, Shin C D, Siyeon K, Yang J H, Yeo I S, Yu I
机构信息
Department of Radiology, Dongshin University, Naju 58245, Korea.
Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
出版信息
Phys Rev Lett. 2016 May 27;116(21):211801. doi: 10.1103/PhysRevLett.116.211801. Epub 2016 May 24.
The RENO experiment has analyzed about 500 live days of data to observe an energy dependent disappearance of reactor ν[over ¯]{e} by comparing their prompt signal spectra measured in two identical near and far detectors. In the period between August of 2011 and January of 2013, the far (near) detector observed 31 541 (290 775) electron antineutrino candidate events with a background fraction of 4.9% (2.8%). The measured prompt spectra show an excess of reactor ν[over ¯]{e} around 5 MeV relative to the prediction from a most commonly used model. A clear energy and baseline dependent disappearance of reactor ν[over ¯]{e} is observed in the deficit of the observed number of ν[over ¯]{e}. Based on the measured far-to-near ratio of prompt spectra, we obtain sin^{2}2θ_{13}=0.082±0.009(stat)±0.006(syst) and |Δm_{ee}^{2}|=[2.62_{-0.23}^{+0.21}(stat)_{-0.13}^{+0.12}(syst)]×10^{-3} eV^{2}.
RENO实验通过比较在两个相同的近探测器和远探测器中测量的反应堆反电子中微子（$\overline{\nu}{e}$）的瞬发信号谱，分析了约500个活时间的数据，以观测反应堆反电子中微子的能量依赖型消失。在2011年8月至2013年1月期间，远（近）探测器观测到31541（290775）个电子反中微子候选事例，本底份额分别为4.9%（2.8%）。测量得到的瞬发谱显示，相对于最常用模型的预测，在5 MeV左右出现了反应堆反电子中微子的过量。从观测到的反电子中微子数量的亏缺中，观测到了明显的与能量和基线相关的反应堆反电子中微子的消失。基于测量得到的瞬发谱的远/近比，我们得到$\sin^{2}2\theta{13}=0.082\pm0.009$（统计）$\pm0.006$（系统），以及$|\Delta m_{ee}^{2}|=[2.62_{-0.23}^{+0.21}$（统计）$_{-0.13}^{+0.12}$（系统）$\times10^{-3}$ eV$^{2}$。
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