AI 中文总结
该研究通过重新审视伽马射线背景与星系形状的交叉相关性来限制暗物质湮灭截面，采用傅里叶空间估计器分析，发现模型无关检验为零结果，模板分析有信号，还得出了对不同暗物质情况的限制及衰变暗物质粒子寿命下限。
AI 中文摘要
我们重新审视未解析的伽马射线背景与星系形状之间的交叉相关性，以限制粒子暗物质的湮灭截面。我们的分析使用了费米大面积望远镜（LAT）14年观测得到的伽马射线光子，以及暗能量调查第3年（DES Y3）和暗能量相机全域数据（DECADE）项目的星系形状目录，从而能够在伽马射线和星系数据集共有的约12000平方度的天空区域探测宇宙学大尺度信号。为了更好地获取大尺度结构的信号，我们采用了傅里叶空间估计器来进行交叉相关性分析，这与之前的DES Y3分析不同。我们发现，在与模型无关的卡方检验中，我们的测量结果与零探测一致，而基于模板的分析在约3倍标准差水平产生了信号。我们的零结果排除了在银河系大小的晕中，质量为2 - 3太电子伏特的类温暗物质在适度的次结构增强因子约为30的情况下增强的湮灭截面。对于约100的更大增强因子，限制变得显著更强，并排除了质量为7 - 40吉电子伏特的暗物质粒子湮灭成底夸克对或陶轻子对时的标准热湮灭截面〈σv〉 = 3×10⁻²⁶立方厘米每秒。基于模板的分析倾向于交叉相关性的幂律伽马射线能量依赖性，但也表明与基于100吉电子伏特左右未解析伽马射线背景的平均强度预期的情况存在偏差。我们进一步考虑了暗物质衰变的情况，并根据衰变通道得出了约10²⁶ - 10²⁷秒的粒子寿命的2倍标准差下限。
英文摘要
We revisit the cross-correlation between the unresolved $γ$-ray background and galaxy shapes to constrain the annihilation cross section of particle dark matter. Our analysis uses $γ$-ray photons from 14 years of observations with the Fermi Large Area Telescope (LAT), together with galaxy shape catalogs from the Dark Energy Survey Year 3 (DES Y3) and the Dark Energy Camera All Data Everywhere (DECADE) project, enabling us to probe cosmological large-scale signals over a common sky area of $\sim 12{,}000\,\mathrm{deg}^2$ shared by the $γ$-ray and galaxy data sets. In order to better access signals from large-scale structure, we employ a Fourier-space estimator for the cross-correlation in contrast to the previous DES Y3 analysis. We find that our measurements are consistent with a null detection in a model-independent $χ^2$ test, while template-based analyses yield signals at the $\sim 3σ$ level. Our null results exclude an enhanced annihilation cross section for wino-like dark matter with a mass of $2-3$ TeV under a modest substructure boost factor of $\sim 30$ in Milky Way-sized halos. For larger boost factors of $\sim 100$, the constraints become significantly stronger and exclude the canonical thermal annihilation cross section $\langle σv \rangle = 3 \times 10^{-26}\,\mathrm{cm}^3/\mathrm{s}$ for a $7-40$ GeV dark matter particle annihilating into $b\bar{b}$ or $τ^{+}τ^{-}$. The template-based analysis favors a power-law $γ$-ray energy dependence of the cross-correlation, but also indicates deviations from that expected based on the mean intensity of the unresolved $γ$-ray background around 100 GeV. We further consider decaying dark matter scenarios and derive $2σ$ lower limits on the particle lifetime of $\sim 10^{26}-10^{27}\,\mathrm{s}$, depending on the decay channel.
Comments15 pages, 9 figures, 1 table. To be submitted to Physical Review D
