不可见中子对湮灭产生的核反冲与LZ事件
Nuclear Recoils from Invisible Neutron-Pair Annihilation and the LZ event
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中文总结 AI 辅助
本研究提出中子对湮灭为不可见标量粒子产生单色核反冲的机制，在氩氙中识别质量窗口，利用DEAP-3600数据给出寿命下限，并指出该过程可探测暗物质转化。
中文摘要 AI 辅助
两个束缚中子可以湮灭为一个携带重子数为二的不可见标量粒子，产生单色核反冲。中子对的移除连接了偶偶核的$0^+$基态，并且对于几种探测器同位素，会留下一个稳定的子核，而单中子移除则会留下放射性子核。在第一子核激发态以下，主要跃迁既不产生核退激，也不产生后续子核衰变。我们在氩和氙中识别了相应的质量窗口，包括高达$108\\,\mathrm{keV}$的氩反冲，并从DEAP-3600数据获得了约$8.5 \times 10^{26}\\,\mathrm{yr}$的部分寿命上限。不同同位素中的反冲线重建了一个共同的不可见粒子质量。发射的标量粒子本身可以是暗物质，使得这些搜索成为探测普通物质转化为暗扇区的探针。
英文摘要
Two bound neutrons can annihilate into a single invisible scalar carrying baryon number two, producing a monochromatic nuclear recoil. Pair removal connects the $0^+$ ground states of even-even nuclei and, for several detector isotopes, leaves a stable daughter where single-neutron removal would leave a radioactive one. Below the first daughter excitation, the leading transition produces neither nuclear de-excitation nor subsequent daughter decay. We identify the corresponding mass windows in argon and xenon, including argon recoils up to $108\,\mathrm{keV}$, and obtain an approximate partial-lifetime bound of $8.5 \times 10^{26}\,\mathrm{yr}$ from DEAP-3600 data. We also discuss this mechanism as a possible origin of the $248\,\mathrm{keV}$ recoil candidate reported by LZ. A ground-state interpretation points to a scalar mass near $1.85\,\mathrm{GeV}$, where daughter excitations are also accessible, and motivates searches for correlated higher-energy recoil lines in argon. Recoil lines in different isotopes reconstruct a common invisible-particle mass. The emitted scalar can itself be dark matter, making these searches a probe of ordinary matter converting into a dark sector.
发表机构
- Tohoku University（东北大学）
- Kavli IPMU (WPI), UTIAS, University of Tokyo（东京大学宇宙线研究所（ Kavli IPMU ））
- University of Sheffield（谢菲尔德大学）
- The University of Manchester（曼彻斯特大学）
机构由 AI 辅助整理，请以论文原文为准。
