利用IndIGO-D在分赫兹波段直接探测极轻暗物质候选体的前景
Prospects for Direct Detection of Ultralight Dark Matter candidates in deci-Hz Band with IndIGO-D
AI总结：
研究拟议的天基分赫兹引力波干涉仪IndIGO-D对极轻暗物质的探测灵敏度，发现其可开辟矢量和张量暗物质的未约束耦合参数空间，还能探测轴子暗物质的轴子-光子耦合。
AI中文摘要：
我们研究了拟议的天基分赫兹引力波干涉仪IndIGO-D对不同类别极轻暗物质的探测灵敏度。IndIGO-D将探测约0.01至10Hz的频率带，该频段介于现有地基和未来天基引力波干涉仪可及频段之间，可覆盖现有仪器无法探测的极轻暗物质质量范围。我们考虑两类互补的信号：一是质量$m_{\rm DM}\sim10^{-17}$至$10^{-14}$eV的标量（伸缩子）、矢量（暗光子，$U(1)_B$和$U(1)_{B-L}$规范群）和张量场相干振荡诱导的干涉位移；二是质量约$m_a\sim10^{-12}$eV的赝标量轴子暗物质诱导的激光偏振变化。对于伸缩子、暗光子和张量，我们采用互相关和BSD excess-power两种处理流程，假设L形和三角形干涉仪布局，以及三种代表性噪声功率谱密度（S1、S2、S3），并基于两年连续观测计算预期灵敏度。我们发现，在不同搜索流程和干涉仪几何结构下，预测灵敏度的差异在同一量级内。特别地，IndIGO-D可在$m_{\rm DM}\sim10^{-16}$至$10^{-14}$eV范围内为矢量和张量暗物质开辟此前未受约束的耦合参数空间，弥合天基和地基实验的灵敏度差距。对于轴子暗物质，我们证明，受光子散粒噪声限制的激光偏振位移互补探测，可探测质量约$m_a\sim10^{-12}$eV的轴子-光子耦合$g_{a\gamma}$，其水平可能优于其他未来实验，且不会降低对引力波的探测灵敏度。
英文摘要：
We investigate the sensitivity of IndIGO-D, a proposed space-based decihertz gravitational-wave interferometer, to different classes of ultralight dark matter. IndIGO-D will probe the $\sim0.01$--$10~\mathrm{Hz}$ frequency band between those accessible to current ground- and future space-based gravitational-wave interferometers, providing access to ultralight dark-matter masses beyond the reach of existing instruments. We consider two complementary signatures: interferometric displacements induced by coherently oscillating scalar (dilaton), vector (dark-photon, $U(1)_B$ and $U(1)_{B-L}$ gauge groups), and tensor fields with masses $m_{\rm DM}\sim10^{-17}$--$10^{-14}~\mathrm{eV}$; and changes in laser polarization induced by pseudoscalar axion dark matter at higher masses, around $m_a\sim10^{-12}~\mathrm{eV}$. For the dilatons, dark photons and tensors, we compute the expected sensitivities using two pipelines -- cross-correlation and BSD excess-power -- assuming L-shaped and triangular interferometer layouts and three representative noise power spectral densities (S1, S2, S3), each for two years of continuous observation. We find that the projected sensitivities agree to within a factor of order unity across the search pipelines and interferometer geometries. In particular, we show that IndIGO-D could open previously unconstrained coupling parameter space for vector and tensor dark matter across $m_{\rm DM}\sim10^{-16}$--$10^{-14}~\mathrm{eV}$, bridging the sensitivity of space- and ground-based experiments. For axion dark matter, we demonstrate that a complementary detection for laser light polarization shifts, limited primarily by photon shot noise, could probe the axion-photon coupling $g_{aγ}$ at masses around $m_a\sim10^{-12}~\mathrm{eV}$ at a level potentially better than that of other future experiments without degrading sensitivity to gravitational waves.
