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arXiv 1706.02249hep-phastro-ph.CO
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DaMaSCUS:地下散射对光暗物质直接探测的影响

DaMaSCUS: The Impact of Underground Scatterings on Direct Detection of Light Dark Matter

Timon Emken, Chris Kouvaris

摘要:

传统的暗物质直接探测实验通过在地下探测器中寻找暗物质粒子与原子核之间的弹性散射事件,对暗物质设置了严格的约束。然而,这些约束在亚GeV质量区域显著减弱,这仅仅是因为光暗物质没有足够的能量来触发探测器,而不管暗物质-核子散射截面如何。即使未来的实验降低了它们的能量阈值,它们仍然会对参数空间视而不见,在参数空间中,暗物质粒子与原子核的相互作用足够强烈,以至于它们失去了足够的能量,当它们到达地下探测器时,无法产生高于实验阈值的信号。因此,如果暗物质处于亚GeV区域并且相互作用强烈,则必须考虑暗物质与地球核的可能地下散射,因为它们显著影响反冲谱和事件率,无论实验是通过DM-核还是DM-电子相互作用探测DM。为了量化这种影响,我们提出了公开可用的地下散射(DaMaSCUS)的暗物质模拟代码,DM轨道通过地球的蒙特卡罗模拟器考虑地下散射。我们的模拟可以精确计算地球上任何给定深度和位置的探测器上暗物质的密度和速度分布。模拟还可以提供地下探测器中的精确反冲光谱以及由地球的这种阴影效应引起的昼夜调制的相位和幅度,最终将不同探测器中预期的调制相关联,这对于决定性地得出昼夜调制是由于暗物质还是不相关背景的结论是重要的。

英文摘要:

Conventional dark matter direct detection experiments set stringent constraints on dark matter by looking for elastic scattering events between dark matter particles and nuclei in underground detectors. However these constraints weaken significantly in the sub-GeV mass region, simply because light dark matter does not have enough energy to trigger detectors regardless of the dark matter-nucleon scattering cross section. Even if future experiments lower their energy thresholds, they will still be blind to parameter space where dark matter particles interact with nuclei strongly enough that they lose enough energy and become unable to cause a signal above the experimental threshold by the time they reach the underground detector. Therefore in case dark matter is in the sub-GeV region and strongly interacting, possible underground scatterings of dark matter with terrestrial nuclei must be taken into account because they affect significantly the recoil spectra and event rates, regardless of whether the experiment probes DM via DM-nucleus or DM-electron interaction. To quantify this effect we present the publicly available Dark Matter Simulation Code for Underground Scatterings (DaMaSCUS), a Monte Carlo simulator of DM trajectories through the Earth taking underground scatterings into account. Our simulation allows the precise calculation of the density and velocity distribution of dark matter at any detector of given depth and location on Earth. The simulation can also provide the accurate recoil spectrum in underground detectors as well as the phase and amplitude of the diurnal modulation caused by this shadowing effect of the Earth, ultimately relating the modulations expected in different detectors, which is important to decisively conclude if a diurnal modulation is due to dark matter or an irrelevant background.

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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