Search for dark-photon dark matter in the SuperMAG geomagnetic field dataset
Search for dark-photon dark matter in the SuperMAG geomagnetic field dataset
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DOI：
10.1103/physrevd.104.095032
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发表时间：
2021-08
影响因子：
5
通讯作者：
M. Fedderke;P. Graham;Derek F. Jackson Kimball;Saarik Kalia
中科院分区：
文献类型：
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作者：
M. Fedderke;P. Graham;Derek F. Jackson Kimball;Saarik Kalia
在我们最近的配套论文 [arXiv:2106.00022] 中，我们指出了超轻动力学混合暗光子暗物质的新特征。该特征是准单色、时间振荡的地球磁场，在地球表面呈现出特定的模式。在这项工作中，我们在地理上分散的地磁站记录的现有非屏蔽磁力计数据中搜索该信号。该数据集来自 SuperMAG Collaboration，包含自 1970 年以来以一分钟节奏进行的测量，其中 $\mathcal{O}(500)$ 站点贡献了全部数据。我们通过将所有站点的磁场测量值投影到一小组全局矢量球谐函数 (VSH) 上来聚合它们，这些全局矢量球谐函数 (VSH) 捕获每个站点的预期信号矢量模式。在每个暗光子相干时间内，我们使用数据驱动技术来估计数据中的宽带背景噪声，并搜索这组 VSH 分量中多余的窄带功率；我们在不同的相干时间内不连贯地堆叠搜索。采用贝叶斯分析方法可以解释暗光子暗物质场的随机性质，我们在暗光子暗物质质量范围 $2\times10^{-18}\,\text{eV} \lesssim m_{A'} \lesssim 7\times10^{-17}\,\text{eV}$ 中设置动力学混合参数的排除界限（对应于频率$6\times 10^{-4}\,\text{Hz}\lesssim f_{A'} \lesssim 2\times 10^{-2}\,\text{Hz}$)。这些限制是对各种现有天体物理限制的补充。尽管我们的主要分析还确定了 SuperMAG 数据集中的许多候选信号，但这些信号似乎要么失败，要么与我们对这些候选信号应用的各种附加稳健性检查存在紧张关系。我们没有报告 SuperMAG 数据集中存在暗光子暗物质信号的有力且重要的证据。
In our recent companion paper [arXiv:2106.00022], we pointed out a novel signature of ultralight kinetically mixed dark-photon dark matter. This signature is a quasi-monochromatic, time-oscillating terrestrial magnetic field that takes a particular pattern over the surface of the Earth. In this work, we present a search for this signal in existing, unshielded magnetometer data recorded by geographically dispersed, geomagnetic stations. The dataset comes from the SuperMAG Collaboration and consists of measurements taken with one-minute cadence since 1970, with $\mathcal{O}(500)$ stations contributing in all. We aggregate the magnetic field measurements from all stations by projecting them onto a small set of global vector spherical harmonics (VSH) that capture the expected vectorial pattern of the signal at each station. Within each dark-photon coherence time, we use a data-driven technique to estimate the broadband background noise in the data, and search for excess narrowband power in this set of VSH components; we stack the searches in distinct coherence times incoherently. Following a Bayesian analysis approach that allows us to account for the stochastic nature of the dark-photon dark-matter field, we set exclusion bounds on the kinetic mixing parameter in the dark-photon dark-matter mass range $2\times10^{-18}\,\text{eV} \lesssim m_{A'} \lesssim 7\times10^{-17}\,\text{eV}$ (corresponding to frequencies $6\times 10^{-4}\,\text{Hz}\lesssim f_{A'} \lesssim 2\times 10^{-2}\,\text{Hz}$). These limits are complementary to various existing astrophysical constraints. Although our main analysis also identifies a number of candidate signals in the SuperMAG dataset, these appear to either fail or be in tension with various additional robustness checks we apply to those candidates. We report no robust and significant evidence for a dark-photon dark-matter signal in the SuperMAG dataset.