发表机构
University College London; University of York（伦敦大学学院; 约克大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分析Fermi-LAT数据，对光子-暗物质弹性散射的有效算符进行扫描，得出银晕的算符分辨灵敏度估计，为相关探测提供了新的约束。
AI 中文摘要
光子-暗物质弹性散射会沿视线方向衰减伽马射线能谱，其探测的算符与暗物质湮灭为光子的算符相同，但速率与暗物质密度呈线性关系，而非二次方关系。我们考虑质量维度为5至7的标准模型规范不变有效算符，其受截断标度Λ抑制，可耦合标量、马约拉纳或狄拉克暗物质与光子。具有非零实光子振幅的主导算符，对于狄拉克暗物质出现在维度5，对于马约拉纳暗物质出现在维度7。在电弱二重态偶极子门户中，为规避直接探测而引入的非弹性分裂也会解除CMB湮灭约束，使得衰减成为三种光子区探测中唯一有效的手段。将此应用于对17年Fermi-LAT Pass 8数据的像素级再分析，针对银心方向，我们得出了来自银晕的光子-暗物质散射的首个算符分辨灵敏度估计：维度5狄拉克偶极子对应的Λ≈0.32 GeV，维度6标量瑞利算符对应的Λ≈0.21 GeV，维度7瑞利家族对应的Λ为0.79–1.06 GeV。该探测范围较弱：其在冷暗物质质量范围内低于EFT有效性阈值，且在偶极子平面上被CMB和直接探测约束所超越。该框架通过伪实验校准，可对任何提供分箱能谱及不确定性、视线柱密度的仪器重新计算灵敏度。
英文摘要
Elastic photon--dark matter scattering attenuates gamma-ray spectra along a line of sight, probing the same operators as dark matter annihilation to photons but at a rate linear, rather than quadratic, in dark matter density. We consider Standard Model gauge-invariant effective operators of mass-dimension 5 to 7, suppressed by a cutoff scale $Λ$, coupling scalar, Majorana or Dirac dark matter to the photon. The leading operators with non-vanishing real-photon amplitudes enter at dimension-5 for Dirac dark matter and dimension-7 for Majorana dark matter. In the electroweak-doublet dipole portal, the inelastic splitting invoked to evade direct detection also closes the CMB annihilation bound, leaving attenuation the only one of the three photon-sector probes that survives. Applying this to a pixel-level reanalysis of 17 years of \textit{Fermi}--LAT Pass~8 data toward the Galactic centre, we derive the first operator-resolved sensitivity estimates for photon--dark matter scattering from the Galactic halo: $Λ\simeq 0.32~\mathrm{GeV}$ for the dimension-5 Dirac dipoles, $0.21~\mathrm{GeV}$ for the dimension-6 scalar Rayleigh operator and $0.79$--$1.06~\mathrm{GeV}$ for the dimension-7 Rayleigh family. The reach is weak: it lies below the EFT-validity threshold across the cold dark matter mass range, and is superseded on the dipole plane by CMB and direct-detection constraints. The framework is calibrated against pseudo-experiments, and recomputes the sensitivity for any instrument that provides a per-bin spectrum with uncertainties and a line-of-sight column density.
Comments26 pages, 5 figures
