摘要
Reactor neutrino experiments build large-scale detector systems to detect neutrinos. In liquid scintillator,a neutral bound state of a positron and an electron, named positronium, can be formed. The spin triplet state is called ortho-positronium（o-Ps）. In this article, an experiment is designed to measure the lifetime of o-Ps, giving a result of 3.1 ns. A PSD parameter based on photon emission time distribution（PETD） was constructed to discriminate e^＋/e^-. Finally, the application of e^＋/e^- discrimination in the JUNO experiment is shown. It helps suppress ^8He/^9Li backgrounds and improves the sensitivity by 0.6 in χ^2 analysis with an assumption of σ=1 ns PMT Transit Time Spread, which will bring a smearing effect to the PETD.
Reactor neutrino experiments build large-scale detector systems to detect neutrinos. In liquid scintillator,a neutral bound state of a positron and an electron, named positronium, can be formed. The spin triplet state is called ortho-positronium（o-Ps）. In this article, an experiment is designed to measure the lifetime of o-Ps, giving a result of 3.1 ns. A PSD parameter based on photon emission time distribution（PETD） was constructed to discriminate e^＋/e^-. Finally, the application of e^＋/e^- discrimination in the JUNO experiment is shown. It helps suppress ^8He/^9Li backgrounds and improves the sensitivity by 0.6 in χ^2 analysis with an assumption of σ=1 ns PMT Transit Time Spread, which will bring a smearing effect to the PETD.
基金
Supported by National Natural Science Foundation of China(11575226,11475197,11205183)
