大亚湾在公里级基线范围内精确测量反应堆反中微子振荡。

Precision Measurement of Reactor Antineutrino Oscillation at Kilometer-Scale Baselines by Daya Bay.

机构信息

Sun Yat-Sen (Zhongshan) University, Guangzhou.

University of Wisconsin, Madison, Wisconsin 53706.

出版信息

Phys Rev Lett. 2023 Apr 21;130(16):161802. doi: 10.1103/PhysRevLett.130.161802.

DOI:10.1103/PhysRevLett.130.161802

PMID:37154643

Abstract

We present a new determination of the smallest neutrino mixing angle θ_{13} and the mass-squared difference Δm_{32}^{2} using a final sample of 5.55×10^{6} inverse beta-decay (IBD) candidates with the final-state neutron captured on gadolinium. This sample is selected from the complete dataset obtained by the Daya Bay reactor neutrino experiment in 3158 days of operation. Compared to the previous Daya Bay results, selection of IBD candidates has been optimized, energy calibration refined, and treatment of backgrounds further improved. The resulting oscillation parameters are sin^{2}2θ_{13}=0.0851±0.0024, Δm_{32}^{2}=(2.466±0.060)×10^{-3} eV^{2} for the normal mass ordering or Δm_{32}^{2}=-(2.571±0.060)×10^{-3} eV^{2} for the inverted mass ordering.

摘要

我们使用最终的 5.55×10^6 个反β衰变（IBD）候选事例样本，其中最后态中子被钆捕获，给出了最小中微子混合角θ_{13}和质量平方差Δm_{32}^{2}的新确定值。该样本是从大亚湾反应堆中微子实验在 3158 天运行中获得的完整数据集选择的。与之前的大亚湾结果相比，IBD 候选事例的选择进行了优化，能量校准得到了改进，背景处理得到了进一步的改善。得到的振荡参数为 sin^{2}2θ_{13}=0.0851±0.0024，对于正常质量顺序，Δm_{32}^{2}=(2.466±0.060)×10^{-3}eV^{2}；对于倒转质量顺序，Δm_{32}^{2}=-(2.571±0.060)×10^{-3}eV^{2}。