Speaker
Description
This poster presents the first measurement of cosmogenic $^8$He isotope production in liquid scintillator at Daya Bay, 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 two independent methods. The results, in units of $10^{-8}\mu^{-1}\rm g^{-1}cm^{2}$, 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. These results supersede previous attempts to determine the ratio of $^8$He to $^9$Li production, which yielded a wide range of limits from 0 to 30%. They also provide future liquid scintillator-based experiments with improved ability to predict cosmogenic backgrounds.
| Poster prize | Yes |
|---|---|
| Given name | Chengzhuo |
| Surname | Yuan |
| First affiliation | Institute of High Energy Physics, Beijing, China |
| Second affiliation | University of Chinese Academy of Sciences, Beijing, China |
| Institutional email | yuanchengzhuo@ihep.ac.cn |
| Gender | Male |
| Collaboration (if any) | Daya Bay Collaboration |
