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arXiv 2101.02503hep-phhep-ex
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在Belle II的非弹性暗物质模型中探索长寿命粒子的性质

Exploring properties of long-lived particles in inelastic dark matter models at Belle II

Dong Woo Kang, P. Ko, Chih-Ting Lu

摘要:

非弹性暗物质模型是研究$O(1)$ GeV以下轻暗物质的一种流行模型。如果DM激发态和基态之间的质量分裂足够小,则共湮灭成为热残余密度的主要通道,DM激发态可以在对撞机尺度上长寿命。我们研究标量和费米子非弹性暗物质模型$ {\cal O}(1) $ GeV DM在Belle II与$ U(1)_D $暗规范对称性破缺到其$Z_2$子群。我们着重研究了DM激发态衰变中的双轻子位移顶点特征。借助Belle II的精确位移顶点探测能力,我们可以探索DM自旋、质量以及DM激发态和基态之间的质量分裂。特别地,我们证明了标量和费米子DM候选者可以区分,DM扇区的质量和质量分裂可以在一些基准点的偏差百分比内确定。此外,还研究了解释μ子$(g-2)_μ$过剩的允许参数空间,它可以在Belle II实验早期的位移顶点分析中被涵盖。

英文摘要:

The inelastic dark matter model is one kind of popular models for the light dark matter (DM) below $O(1)$ GeV. If the mass splitting between DM excited and ground states is small enough, the co-annihilation becomes the dominant channel for thermal relic density and the DM excited state can be long-lived at the collider scale. We study scalar and fermion inelastic dark matter models for $ {\cal O}(1) $ GeV DM at Belle II with $ U(1)_D $ dark gauge symmetry broken into its $Z_2$ subgroup. We focus on dilepton displaced vertex signatures from decays of the DM excited state. With the help of precise displaced vertex detection ability at Belle II, we can explore the DM spin, mass and mass splitting between DM excited and ground states. Especially, we show scalar and fermion DM candidates can be discriminated and the mass and mass splitting of DM sector can be determined within the percentage of deviation for some benchmark points. Furthermore, the allowed parameter space to explain the excess of muon $(g-2)_μ$ is also studied and it can be covered in our displaced vertex analysis during the early stage of Belle II experiment.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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