Cohen Timothy, Murase Kohta, Rodd Nicholas L, Safdi Benjamin R, Soreq Yotam
Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, USA.
Center for Particle and Gravitational Astrophysics; Department of Physics; Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Phys Rev Lett. 2017 Jul 14;119(2):021102. doi: 10.1103/PhysRevLett.119.021102. Epub 2017 Jul 13.
Utilizing the Fermi measurement of the γ-ray spectrum toward the Inner Galaxy, we derive some of the strongest constraints to date on the dark matter (DM) lifetime in the mass range from hundreds of MeV to above an EeV. Our profile-likelihood-based analysis relies on 413 weeks of Fermi Pass 8 data from 200 MeV to 2 TeV, along with up-to-date models for diffuse γ-ray emission within the Milky Way. We model Galactic and extragalactic DM decay and include contributions to the DM-induced γ-ray flux resulting from both primary emission and inverse-Compton scattering of primary electrons and positrons. For the extragalactic flux, we also calculate the spectrum associated with cascades of high-energy γ rays scattering off of the cosmic background radiation. We argue that a decaying DM interpretation for the 10 TeV-1 PeV neutrino flux observed by IceCube is disfavored by our constraints. Our results also challenge a decaying DM explanation of the AMS-02 positron flux. We interpret the results in terms of individual final states and in the context of simplified scenarios such as a hidden-sector glueball model.
利用费米对朝向银河系内部的γ射线光谱的测量，我们得出了迄今为止对质量范围从数百兆电子伏特到超过十亿电子伏特的暗物质（DM）寿命的一些最强限制。我们基于轮廓似然性的分析依赖于来自费米8期的413周数据，能量范围从200兆电子伏特到2太电子伏特，以及银河系内弥漫γ射线发射的最新模型。我们对银河系和河外暗物质衰变进行建模，并考虑了初级发射以及初级电子和正电子的逆康普顿散射对暗物质诱导的γ射线通量的贡献。对于河外通量，我们还计算了与高能γ射线在宇宙背景辐射上散射产生的级联相关的光谱。我们认为，我们的限制不支持用衰变暗物质来解释冰立方观测到的10太电子伏特 - 1拍电子伏特中微子通量。我们的结果也对AMS - 02正电子通量的衰变暗物质解释提出了挑战。我们从单个末态以及简化情景（如隐藏区胶球模型）的背景下解释了这些结果。
