Mass Hierarchy by Reactor neutrinos 5 JUNO Daya

Mass Hierarchy by Reactor neutrinos 5

江门中微子实验JUNO选址 Daya Bay Huizhou Lufeng Yangjiang Taishan Status Operational Planned Under construction Power 17. 4 GW 18. 4 GW • 质量顺序 • 混合参数精确测 量 Lufeng Huizhou • 超新星中微子 • 地球中微子 • 大气中微子 JUNO • 不活跃中微子 • …… Previous site candidate Daya Bay Kaiping, Jiangmen, Guangdong DY B Taishan NPP Yangjiang NPP 6

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物理要求 • Nominal assumption: • • • Detector size: 20 kt Energy resolution: 3% Thermal power: 36 GW Baseline: ~53 km MH sensitivity: 3 s for 6 yrs 3 years, 2 s 6 years, 3 s 8

重建流程 • vertex reconstruction relative hit time likelihood method first hit time of each PMT • visible energy reconstruction charge likelihood method vertex reconstructed in the first step and PE number of each PMT 11

液闪发光时间特性 • point-like events , define residual time where ti : first hit time of ith PMT tof : time of flight for scintillation photon t 0 : real start time of an event • for LS detector, the residual time will obey the following formula • where : systematic uncertainty of hit time : different time constant of LS 12

基于时间信息的极大似然法 ① initial vertex : charge center method; ② calculate ③ residual time distribution can be expressed as ④ jointed time likelihood function: 13

顶点重建结果 e+ P=0 Me. V (0, 0, 10 m) Mean = -3. 464 mm Sigma = 86. 97 mm e+ P=6. 469 Me. V (0, 0, 10 m) Mean = -1. 934 mm Sigma = 32. 73 mm 14

考虑PMT时间分辨 • Transit time spread of PMT • TTS = 2. 354 Z resolution @ ball center 15

可见能量重建 • charge likelihood function • probability of non-hit • Probability for readout charge is • The expected PE number where the vertex r is determined by hit time likelihood method 16