论文标题
长期暴露于银河光环中腐烂暗物质的长期限制
Long-Exposure NuSTAR Constraints on Decaying Dark Matter in the Galactic Halo
论文作者
论文摘要
我们提出了两个补充的Nustar X射线搜索，以在银河系Halo中以单能光子的形式腐烂到keV规模的暗物质。首先，我们利用跨检测器平面的未关注杂散光的已知强度模式（来自弥漫源的主要光子来源），使用$ {\ sim} $ 7-ms/tetter深空空白曝光，将天体物理发射与内部仪器背景分开。在第二个中，我们提出了完整的Nustar仪器背景的更新的参数模型，使我们能够利用独立的$ {\ sim}的统计功率$ 20-ms/detector堆叠的曝光，分布在天空中。我们没有使用这两种方法找到异常的X射线线的证据，我们对无菌 - 中性群质量的活动 - 肌电混合角$ \ sin^2（2θ）$设置了限制，6--40 keV。第一个关键结果是，我们强烈不利于$ {\ sim} $ 7盎司无菌中微子衰减，将其衰减到3.5盎司光子中。第二是，我们在带有质量的无菌中微子上获得了领先的限制，$ {\ sim} $ 15--18 keV和$ {\ sim} $ 25--40 kev，到达或延伸至大爆炸核合成限制。结合先前的结果，中微子最小标准模型（$ν$ msm）的参数空间现在几乎已关闭。
We present two complementary NuSTAR x-ray searches for keV-scale dark matter decaying to mono-energetic photons in the Milky Way halo. In the first, we utilize the known intensity pattern of unfocused stray light across the detector planes -- the dominant source of photons from diffuse sources -- to separate astrophysical emission from internal instrument backgrounds using ${\sim}$7-Ms/detector deep blank-sky exposures. In the second, we present an updated parametric model of the full NuSTAR instrument background, allowing us to leverage the statistical power of an independent ${\sim}$20-Ms/detector stacked exposures spread across the sky. Finding no evidence of anomalous x-ray lines using either method, we set limits on the active-sterile mixing angle $\sin^2(2θ)$ for sterile-neutrino masses 6--40 keV. The first key result is that we strongly disfavor a ${\sim}$7-keV sterile neutrino decaying into a 3.5-keV photon. The second is that we derive leading limits on sterile neutrinos with masses ${\sim}$15--18 keV and ${\sim}$25--40 keV, reaching or extending below the Big Bang Nucleosynthesis limit. In combination with previous results, the parameter space for the Neutrino Minimal Standard Model ($ν$MSM) is now nearly closed.
