标题： 宇宙射线缪子在大亚湾液体闪烁体中产生的$^8$氦同位素产率的首次测量 显示英文标题

标题： First measurement of the yield of $^8$He isotopes produced in liquid scintillator by cosmic-ray muons at Daya Bay

摘要： Daya Bay首次测量了液态闪烁体中宇宙射线产生的$^8$氦同位素的生成，采用了一种创新的方法来识别$^8$氦及其子同位素$^8$锂的级联衰变。我们还使用已建立的方法测量了$^9$锂同位素的生成产率。 结果的单位为10$^{-8}\mu^{-1}$g$^{-1}$cm$^{2}$，分别为0.307$\pm$0.042，0.341$\pm$0.040，和0.546$\pm$0.076 对于$^8$He，以及6.73$\pm$0.73，6.75$\pm$0.70，和13.74$\pm$0.82 对于$^9$Li 在平均缪子能量分别为63.9~GeV，64.7~GeV，和143.0~GeV时。 测量的$^8$He同位素的产率比任何其他宇宙成因同位素产率的测量结果低一个数量级以上。 它取代了以前尝试确定$^8$He与$^9$Li产率比的结果，这些结果得出的范围从0%到30%不等。 这些结果为基于液态闪烁体的未来实验提供了更好的预测宇宙成因背景的能力。 显示英文摘要

摘要： Daya Bay presents the first measurement of cosmogenic $^8$He isotope production in liquid scintillator, using an innovative method for identifying cascade decays of $^8$He and its child isotope, $^8$Li. We also measure the production yield of $^9$Li isotopes using well-established methodology. The results, in units of 10$^{-8}\mu^{-1}$g$^{-1}$cm$^{2}$, are 0.307$\pm$0.042, 0.341$\pm$0.040, and 0.546$\pm$0.076 for $^8$He, and 6.73$\pm$0.73, 6.75$\pm$0.70, and 13.74$\pm$0.82 for $^9$Li at average muon energies of 63.9~GeV, 64.7~GeV, and 143.0~GeV, respectively. The measured production rate of $^8$He isotopes is more than an order of magnitude lower than any other measurement of cosmogenic isotope production. It replaces the results of previous attempts to determine the ratio of $^8$He to $^9$Li production that yielded a wide range of limits from 0 to 30\%. The results provide future liquid-scintillator-based experiments with improved ability to predict cosmogenic backgrounds.