The long-standing Galactic center gamma-ray excess could be explained by GeV dark matter (DM) annihilation, but the DM interpretation seems to conflict with recent joint limits from different astronomical scale observations such as dwarf spheroidal galaxies, the Milky Way halo, and galaxy groups/clusters. Motivated by ⁸Be and ⁴He anomalous transitions with possible new interactions mediated by a vector boson X, we consider a small fraction of DM mainly annihilating into a pair of on-shell vector bosons followed by in this paper. The Galactic center gamma-ray excess is explained by this DM cascade annihilation. The gamma rays are mainly from inverse Compton scattering emission, and the DM cascade annihilation could be compatible with joint astrophysical limits and meanwhile be allowed by AMS-02 positron observation. The direct detection of this model is also discussed.

长期存在的银河系中心伽马射线过剩可以用 GeV 暗物质 (DM) 湮灭来解释，但 DM 的解释似乎与最近来自不同天文尺度观测的联合限制相冲突，例如矮球形星系、银河系晕和星系群/星系团。受⁸ Be 和^{4 He 异常跃迁以及由矢量玻色子}X介导的可能的新相互作用的推动，我们认为一小部分 DM 主要湮灭成一对壳上矢量玻色子，然后在本文中。银河系中心伽马射线过剩可以通过这种 DM 级联湮灭来解释。伽马射线主要来自逆康普顿散射发射，DM级联湮没可以与联合天体物理极限兼容，同时AMS-02正电子观测允许。还讨论了该模型的直接检测。