用河外μ中微子约束原初黑洞和原初曲率功率谱
Constraining primordial black holes and primordial curvature power spectrum with extragalactic muon neutrino
AI总结：
研究由WIMPs和PBHs组成的混合暗物质情景，通过分析PBHs周围WIMP湮灭产生的河外中微子通量，得出PBHs中暗物质比例上限及原初曲率功率谱上限，为相关研究提供了新约束。
AI中文摘要：
我们研究了一个由弱相互作用大质量粒子（WIMPs）和原初黑洞（PBHs）组成的混合暗物质情景。PBH形成后，WIMPs可在其上吸积，形成超紧凑微晕（UCMHs）。UCMHs内的WIMP数密度相较于经典暗物质晕模型显著增强，导致更高的WIMP湮灭率。以往研究主要关注相关伽马射线通量，我们研究此类湮灭产生的河外中微子通量。考虑湮灭通道μ⁺μ⁻、τ⁺τ⁻和νμνμ，分析两类中微子事件：上行和含于探测器内的事件。通过要求PBHs周围WIMP湮灭产生的中微子通量不超过大气中微子背景，我们得出了冰立方实验一年曝光时间下PBHs中暗物质比例（fPBH）的上限。这些限制取决于湮灭通道、WIMP和PBH的质量以及中微子事件类型。最强限制来自νμνμ通道，对于mχ = 10³ GeV和MPBH = 10³ M⊙的含于探测器内（上行）事件，fPBH约为10⁻⁴（4×10⁻⁵）。基于对PBHs的这些限制，我们进一步得出原初曲率功率谱PR的上限。从最强限制来看，在k ∼ 3×10¹² Mpc⁻¹尺度下，PR约为10⁻¹.⁶⁵。
英文摘要：
We investigate a mixed dark matter scenario comprising weakly interacting massive particles (WIMPs) and primordial black holes (PBHs). After PBH formation, WIMPs can accrete onto them, forming ultracompact minihalos (UCMHs). The resulting WIMP number density within UCMHs is significantly enhanced compared to classical dark matter halo models, leading to a higher WIMP annihilation rate. Previous studies have focused mainly on the associated gamma-ray flux, we investigate the extragalactic neutrino flux from such annihilation. Considering the annihilation channels $μ^{+}μ^{-}$, $τ^{+}τ^{-}$, and $ν_μ\barν_μ$, we analyze two classes of neutrino events: upward and contained events. By requiring the neutrino flux from WIMP annihilation around PBHs does not exceed the atmospheric neutrino background, we derive upper limits on the fraction of dark matter in PBHs ($f_{\rm PBH}$) for a one-year exposure of the IceCube experiment. These limits depend on the annihilation channel, the masses of the WIMP and PBH, and the neutrino event type. The strongest constraints come from the $ν_μ\barν_μ$ channel, yielding $f_{\rm PBH} \sim 10^{-4}$ ($4\times 10^{-5}$) for contained (upward) events with $m_χ=10^{3}$ GeV and $M_{\rm PBH}=10^{3} M_{\odot}$. Based on these bounds on PBHs, we further derive upper limits on the primordial curvature power spectrum $\mathcal{P}_{\mathcal{R}}$. From our strongest constraint, we obtain $\mathcal{P}_{\mathcal{R}} \sim 10^{-1.65}$ at the scale $k\sim 3\times 10^{12}~\mathrm{Mpc^{-1}}$.
