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arXiv 2204.04889hep-ph
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Muon $(g-2)$ 与热 WIMP 暗物质在 ${\rm U(1)}_{L_\mu-L_\tau}$ 模型中的研究

Muon $(g-2)$ and Thermal WIMP DM in ${\rm U(1)}_{L_μ-L_τ} $ Models

Seungwon Baek, Jongkuk Kim, P. Ko

AI总结:

该研究通过引入暗希格斯玻色子,在U(1)_{L_μ-L_τ}模型中解耦了Z'质量与暗物质质量的紧密关联,为轻Z'区域的热WIMP暗物质提供了更广泛的质量可能性,同时保持对缪子(g-2)的显著贡献。

摘要:

${\rm U(1)}_{L_\mu- L_\tau}$ 模型在标准模型(SM)费子内容下是无反常的,并且可以在 $\Delta a_\mu\sim O(10) \times 10^{-10}$ 的水平上对缪子 $(g-2)$ 做出显著贡献,其中 $M_{Z'} \sim O(10-100)$ MeV,$g_X \sim (4 - 8) \times 10^{-4}$。在这个轻 $Z'$ 区域,有人声称如果 $M_{\rm DM} \sim M_{Z'}/2$,该模型也可以包含热 WIMP 暗物质(DM)。这种设置依赖于暗物质粒子通过 $Z'$ 介导的 $s$ 道湮灭成标准模型粒子。在这项工作中,我们表明通过考虑暗希格斯玻色子($H_1$)的贡献,对于标量暗物质和自旋-1/2 暗物质,$M_{Z'}$ 和 $M_{\rm DM}$ 之间的这种紧密关系可以被规避或消除。暗希格斯玻色子扮演着重要角色,不仅因为它赋予暗光子质量,还因为它引入了额外的暗物质湮灭通道,包括新的最终态,如 $H_1 H_1$、$Z' Z'$ 和 $Z' H_1$。因此,该模型不再需要 $Z'$ 玻色子与暗物质质量之间的紧密关联 $M_{\rm DM} \sim M_{Z'}/2$,从而允许标量和费米子暗物质类型具有更广泛的质量可能性。我们详细探索了各种情景,其中 $U(1)$ 对称性要么完全破缺,要么部分保留为离散对称性 $Z_2$ 或 $Z_3$。这种方法拓宽了模型在轻 $Z'$ 区域容纳各种 WIMP 暗物质现象的能力,在该区域缪子 $(g-2)_\mu$ 是模型的一个敏感探针。

英文摘要:

The ${\rm U(1)}_{L_μ- L_τ}$ model is anomaly-free with the Standard Model (SM) fermion content, and can make substantial contributions to the muon $(g-2)$ at the level of $Δa_μ\sim O(10) \times 10^{-10}$ for $M_{Z'} \sim O(10-100)$ MeV and $g_X \sim (4 - 8) \times 10^{-4}$. In this light $Z'$ region, it was claimed that the model can also incorporate thermal WIMP dark matter (DM) if $M_{\rm DM} \sim M_{Z'}/2$. This setup relies on DM particles annihilating into SM particles through a $Z'$-mediated $s$-channel. In this work, we show that this tight relationship between $M_{Z'}$ and $M_{\rm DM}$ can be evaded or nullified both for scalar and spin-1/2 DM by considering the contributions from the dark Higgs boson ($H_1$). The dark Higgs boson plays an important role, not only because it gives mass to the dark photon but also because it introduces additional DM annihilation channels, including new final states such as $H_1 H_1$, $Z' Z'$, and $Z' H_1$. As a result, the model does not require a close mass correlation between the $Z'$ boson and dark matter $M_{\rm DM} \sim M_{Z'}/2$ any longer, allowing for a broader range of mass possibilities for both scalar and fermionic dark matter types. We explore in great details various scenarios where the $U(1)$ symmetry is either fully broken or partially remains as discrete symmetries, $Z_2$ or $Z_3$. This approach broadens the model's capacity to accommodate various WIMP dark matter phenomena in the light $Z'$ region where the muon $(g-2)_μ$ makes a sensitive probe of the model.

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