非弹性单态-双重态费米子暗物质与248 keV LZ事例
Inelastic Singlet-Doublet Fermion Dark Matter in light of the 248 keV LZ event
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中文总结 AI 辅助
针对LZ实验248 keV暗物质事例，研究单态-双重态费米子暗物质模型，利用非弹性散射解释低能事例缺失，并引入标量三重态产生劈裂和中微子质量。
中文摘要 AI 辅助
最近，LUX-ZEPLIN (LZ) 合作组报道在核反冲能量为 $248\pm23_{\rm stat}\pm23_{\rm sys}$ keV 处观测到一个暗物质-原子核散射事例，对应曝光量为2.84吨·年。在预测能谱中较低核反冲能量处没有事例，这一现象如果底层过程是非弹性暗物质-原子核散射，则可自然解释。受此启发，我们研究了单态-双重态费米子暗物质模型，其中暗物质由两个赝狄拉克态组成：较轻态的Majorana性质在树级上完全禁止了$Z$介导的弹性散射，而相同的态通过$Z$交换实现非弹性暗物质-原子核散射，任何残余的弹性散射仅通过受抑制的Higgs介导通道进行。我们进一步用$Z_2$偶标量三重态扩展该模型，该三重态既负责产生赝狄拉克劈裂，又通过II型跷跷板机制实现Majorana中微子质量。
英文摘要
Recently, the LUX-ZEPLIN (LZ) collaboration reported the observation of a single dark matter (DM)-nucleus scattering event at a nuclear recoil energy of $248\pm23_{\rm stat}\pm23_{\rm sys}$ keV, corresponding to an exposure of 2.84 tonne-year. The absence of events at lower nuclear recoil energies in the predicted spectrum is naturally explained if the underlying process is inelastic DM-nucleus scattering. Motivated by this, we investigate the singlet-doublet fermion DM model, in which the DM consists of two pseudo-Dirac states: the Majorana nature of the lighter state forbids tree level $Z$-mediated elastic scattering identically, while the same states enable inelastic DM-nucleus scattering via $Z$ exchange, with any residual elastic scattering proceeding only through a suppressed Higgs-mediated channel. We further extend the model with a $Z_2$-even scalar triplet, which is responsible both for generating the pseudo-Dirac splitting and for realizing Majorana neutrino masses via the Type-II seesaw mechanism.
发表机构
- Indian Institute of Technology Guwahati（印度理工学院古瓦哈提分校）
- Indian Institute of Technology Hyderabad（印度理工学院海德拉巴分校）
- Institute of Mathematical Sciences（数学科学研究所）
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