标题： 来自费米伽马射线太空望远镜（Fermi-LAT）各向同性弥漫伽马射线测量对宇宙暗物质湮灭的限制 显示英文标题

标题： Constraints on Cosmological Dark Matter Annihilation from the Fermi-LAT Isotropic Diffuse Gamma-Ray Measurement

摘要： 首次发布的费米大面积望远镜（Fermi-LAT）对各向同性弥散伽马射线辐射的测量结果与单一幂律模型很好地吻合，并未显示出20至100 GeV能量范围内暗物质源占主导贡献的任何迹象。 我们利用这一测量通量的绝对大小和光谱形状，推导出三种通用暗物质候选者的截面限制：湮灭为夸克、带电轻子以及单色光子。 来自湮灭暗物质的预测伽马射线通量受到暗物质分布的强烈影响，通过使用不同可用的物质结构形成结果，我们评估了这些不确定性。 我们还量化了暗物质约束如何依赖于假设的传统背景以及宇宙对高能伽马射线的透明度。 在合理的背景和暗物质结构场景下（但并非在我们考虑的所有场景中），可以排除费米-LAT和PAMELA实验测量到的电子和正电子过剩现象的解释模型。 推导出的限制也开始探测热产生遗迹（例如，在最小超对称模型中）主要湮灭为夸克的预期截面。 对于单色伽马射线信号，目前的测量仅限制了具有非常强信号的暗物质情景。 显示英文摘要

摘要： The first published Fermi large area telescope (Fermi-LAT) measurement of the isotropic diffuse gamma-ray emission is in good agreement with a single power law, and is not showing any signature of a dominant contribution from dark matter sources in the energy range from 20 to 100 GeV. We use the absolute size and spectral shape of this measured flux to derive cross section limits on three types of generic dark matter candidates: annihilating into quarks, charged leptons and monochromatic photons. Predicted gamma-ray fluxes from annihilating dark matter are strongly affected by the underlying distribution of dark matter, and by using different available results of matter structure formation we assess these uncertainties. We also quantify how the dark matter constraints depend on the assumed conventional backgrounds and on the Universe's transparency to high-energy gamma-rays. In reasonable background and dark matter structure scenarios (but not in all scenarios we consider) it is possible to exclude models proposed to explain the excess of electrons and positrons measured by the Fermi-LAT and PAMELA experiments. Derived limits also start to probe cross sections expected from thermally produced relics (e.g. in minimal supersymmetry models) annihilating predominantly into quarks. For the monochromatic gamma-ray signature, the current measurement constrains only dark matter scenarios with very strong signals.