广义手征 $U(1)_{B-L}$ 框架下的非弹性标量暗物质与 LZ 248 keV 事件
Generalized Chiral $U(1)_{B-L}$ with Inelastic Scalar Dark Matter for the LZ 248 keV Event
- Institute for Convergence of Basic Studies, Seoul National University of Science and Technology（首尔科学技术大学基础融合研究所）
- Department of Physics, Indian Institute of Science Education and Research - Bhopal（印度科学教育与研究学院博帕尔分校物理系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
针对LZ 248 keV事件，提出广义手征U(1)_{B-L}框架下的非弹性标量暗物质模型，通过质量劈裂和Z'介导的吸热散射解释高能核反冲，并确定满足遗迹丰度和实验约束的参数空间。
AI中文摘要：
LZ 合作组最近报道的高能核反冲事件，其能量 $E_R\simeq248$ keV，背景-only 显著性为 $2.6\sigma$，为超越传统弹性图像的暗物质散射提供了一个有趣的窗口。我们在广义手征 $U(1)_{B-L}$ 框架下研究了一种非弹性标量暗物质情景。对称性破缺后，暗区标量产生两个近简并态，具有较小的质量劈裂。较轻的态作为暗物质候选者，并与 $Z'$ 玻色子发生非对角耦合，导致吸热非弹性散射。由此产生的运动学抑制了低速暗物质的贡献，同时使高速尾部对高能核反冲的贡献日益重要。我们确定了与观测到的遗迹丰度和当前实验约束相一致的参数空间，并讨论了与近期 LZ 观测相关的非弹性散射运动学，以及相关 $Z'$ 玻色子的互补对撞机前景。
英文摘要：
The high-energy nuclear recoil event with $E_R\simeq248$ keV recently reported by the LZ collaboration, with a background-only significance of $2.6σ$, offers an intriguing window into dark matter scattering beyond the conventional elastic picture. We study an inelastic scalar dark matter scenario within a generalized chiral $U(1)_{B-L}$ framework. After symmetry breaking, the dark sector scalar gives rise to two nearly degenerate states with a small mass splitting. The lighter state serves as the dark matter candidate and couples off-diagonally to the $Z'$ boson, leading to endothermic inelastic scattering. The resulting kinematics suppress the contribution from low-velocity dark matter while making the high-velocity tail increasingly relevant for nuclear recoils at higher energies. We identify the parameter space consistent with the observed relic abundance and current experimental constraints, and discuss the inelastic scattering kinematics relevant to the recent LZ observation, together with the complementary collider prospects for the associated $Z'$ boson.
