Title: New Spallation Background Rejection Techniques to Greatly Improve the Solar Neutrino Sensitivity of JUNO Show Chinese title

Title: 新的散裂背景抑制技术以显著提高JUNO的太阳中微子灵敏度

Abstract: While the potential of the Jiangmen Underground Neutrino Observatory (JUNO) to measure solar neutrinos is known, realizing this potential requires new techniques to reduce detector backgrounds. One of the most serious backgrounds is due to the beta decays of unstable nuclei produced through muon breakup (spallation) of nuclei. This background is much more significant in JUNO compared to Super-Kamiokande due to JUNO's shallower depth and its lack of directional information. We present the first detailed theoretical calculations of spallation backgrounds in JUNO, showing the underlying physical processes and new ways to cut backgrounds while preserving signals. A key point is showing the importance of neutron tagging to identify hadronic showers, which are rare but produce almost all of the dangerous isotopes. With our new techniques, JUNO will be able to reduce deadtime (signal loss) by a factor of five and to reduce the running time needed to meet sensitivity goals by a factor of two. This will give JUNO greatly improved sensitivity to $^8$B and $hep$ solar neutrinos, as we will explore in a separate paper. Show Chinese abstract

Abstract: 虽然江门地下中微子观测站（JUNO）测量太阳中微子的潜力已知，但实现这一潜力需要新的技术来减少探测器背景。 其中最严重的背景来自于通过μ子破碎（溅射）产生的不稳定核的β衰变。 由于JUNO的深度较浅且缺乏方向信息，这种背景在JUNO中比超级神冈探测器更为显著。 我们首次对JUNO中的溅射背景进行了详细的理论计算，展示了基本的物理过程以及在保留信号的同时减少背景的新方法。 一个关键点是展示中子标记的重要性，以识别强子簇射，这些簇射虽然罕见，但几乎产生了所有危险的同位素。 通过我们的新技术，JUNO将能够将死时间（信号损失）减少五倍，并将满足灵敏度目标所需的运行时间减少两倍。 这将使JUNO对$^8$B 和$hep$太阳中微子的灵敏度大大提升，我们将在另一篇论文中进行探讨。