Abstract:
Solar neutrinos can interact with liquid xenon (LXe) in dark matter detectors through coherent elastic neutrino-nucleus scattering (CEvNS), generating signals that closely mimic dark matter (DM) interactions. This phenomenon, often referred to as the 'neutrino fog,' presents a significant challenge to direct DM detection efforts. The XENONnT detector, known for its large exposure and low background, offers an exceptional opportunity to investigate this interaction.
At the heart of XENONnT is a low-background, two-phase time projection chamber with a 5.9-tonne liquid xenon target. Utilizing data from XENONnT's first and second science runs, we conducted a search for CEvNS signals of solar B-8 neutrinos, resulting in 37 observed events above 0.5 keV, with the 26.4 (+1.4/-1.3) background events expected, leading to the rejection of the background-only hypothesis with a statistical significance of 2.73 sigma. This marks the first direct detection of nuclear recoils from solar neutrinos using a dark matter detector.
In this seminar, we will present a detailed view of the search for solar B-8 CEvNS signals. This includes the implementation of novel low-threshold analysis techniques, suppression of dominant accidental coincidence backgrounds, and advanced modeling of multidimensional signal and background distributions in statistical inference, all of which significantly enhance sensitivity to solar B-8 neutrinos.
About the speaker:
刘可欣，清华大学物理系博士生，获得清华大学“未来学者”奖学金支持。XENON合作组成员，“信号与探测器物理”分析小组组长。XENONnT实验测量太阳硼-8中微子信号物理分析工作的主要负责人之一，完成了最大实验本底（偶然符合本底）的压低、预测和验证工作，论文共同通讯作者。因太阳中微子物理分析工作曾获研究生国家奖学金，获IDM2024暗物质大会直接探测实验类别最佳口头报告奖。
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Meeting ID 会议号: 84020898104
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