Cosmological constraints on the velocity-dependent baryon-dark matter coupling
Cosmological constraints on the velocity-dependent baryon-dark matter coupling
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DOI：
10.1088/1475-7516/2019/09/020
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发表时间：
2019-02
影响因子：
6.4
通讯作者：
J. Ooba;H. Tashiro;K. Kadota
中科院分区：
文献类型：
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作者：
J. Ooba;H. Tashiro;K. Kadota
利用普朗克微波背景辐射（CMB）和斯隆数字巡天（SDSS）莱曼-α森林观测数据，给出了MeV以下暗物质质量的重子-暗物质相互作用截面的宇宙学约束.为了探索暗物质质量m × <$1MeV，除了重子-暗物质耦合存在的声学振荡阻尼外，暗物质的自由流效应可以抑制可观测到的小尺度密度涨落，我们采用了类似于传统暖暗物质的暗物质自由流近似处理.我们证明了重子-暗物质横截面边界的质量依赖性（对于暗物质质量下降到m × 1.5 keV），与之前文献中声称的MeV尺度以下的轻暗物质横截面约束的暗物质质量独立性相反。我们还研究了标量原初谱中重子-暗物质耦合与运行谱指数之间的简并度。我们发现，这种简并是弱的和重子暗物质耦合的约束是不受我们的MCMC分析中的运行光谱指数列入。
We present the cosmological constraints on the cross section of baryon-dark matter interactions for the dark matter mass below the MeV scale from the Planck CMB (cosmic microwave background) and SDSS (Sloan Digital Sky Survey) Lyman-α forest data. To explore the dark matter mass mχ≲ 1 MeV for which the dark matter's free-streaming effect can suppress the observable small scale density fluctuations, in addition to the acoustic oscillation damping in existence of the baryon-dark matter coupling, we apply the approximated treatment of dark matter free-streaming analogous to that of the conventional warm dark matter. We demonstrate the mass dependence of the baryon-dark matter cross section bounds (for the dark matter mass down to mχ ∼ 5 keV), in contrast to the dark matter mass independence of the cross section constraints for the light dark matter below the MeV scale claimed in the previous literature. We also investigate the degeneracy between the baryon-dark matter coupling and the running spectral index in the scalar primordial spectrum. We find that this degeneracy is weak and the constraint on the baryon-dark matter coupling is not affected by the inclusion of the running spectral index in our MCMC analysis.