大体积中微子望远镜中物质诱导暗物质衰变的新特征
Novel Signatures of Matter-Induced Dark Matter Decay in Large-Volume Neutrino Telescopes
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中文总结 AI 辅助
该研究提出物质诱导暗物质衰变的两种机制，计算缪子分布，表明相关参数空间可在IceCube等大体积中微子望远镜产生可观测事件率，还探讨了IceCube对特定带电粒子衰变多缪子事件的灵敏度。
中文摘要 AI 辅助
大体积中微子望远镜为寻找衰变暗物质提供了独特机会，这类暗物质事件包含一对从共同顶点出射的高能、高度非准直的缪子径迹，这类事件的标准模型背景可忽略不计，将是新物理的显著特征。然而，常规暗物质湮灭或衰变受到过强约束，无法产生可观测的此类事件率。因此，我们考虑如下场景：激发态暗物质在真空中寿命极长，但在普通物质存在时衰变得快得多。我们提出该机制的两种实现方式：第一种，由普通物质产生的长程标量场修改暗区质量谱，在地球附近使衰变χ₂→χ₁Z'在运动学上允许，而在真空中该衰变是禁戒的；第二种，标量背景诱导重Z'与光子的动力学混合，在富物质环境中大幅增强三体衰变χ₂→χ₁μ⁺μ⁻。我们计算了缪子能量和张开角的分布，表明可行的参数空间区域能在IceCube、KM3NeT及其他大体积中微子望远镜中产生可观测的事件率，同时符合现有约束。我们还简要探讨了IceCube对质量≥1 TeV的宇宙学长寿命带电粒子衰变产生的多缪子事件的灵敏度。
英文摘要
Large-volume neutrino telescopes offer a unique opportunity to search for decaying dark matter through events containing a pair of energetic, highly non-collimated muon tracks emerging from a common vertex. Such events would have negligible Standard Model backgrounds and would constitute a striking signature of new physics. Conventional dark matter annihilation or decay, however, is too strongly constrained to produce an observable rate of such events. We therefore consider scenarios in which an excited dark matter state is extremely long-lived in vacuum but decays much more rapidly in the presence of ordinary matter. We present two realizations of this mechanism. In the first, a long-range scalar field sourced by ordinary matter modifies the dark-sector mass spectrum, kinematically opening the decay $χ_2 \rightarrow χ_1 Z'$ near the Earth while leaving it forbidden in vacuum. In the second, the scalar background induces kinetic mixing between a heavy $Z'$ and the photon, greatly enhancing the three-body decay $χ_2\toχ_1μ^+μ^-$ in matter-rich environments. We calculate the resulting distributions of muon energies and opening angles and show that viable regions of parameter space can yield observable event rates in IceCube, KM3NeT, and other large-volume neutrino telescopes while remaining consistent with existing constraints. We also briefly consider the sensitivity of IceCube to multi-muon events produced by the decays of cosmologically long-lived charged particles with masses $\gtrsim 1$ TeV.
