Dipartimento di Fisica ed Astronomia, Università di Padova, Via Marzolo 8, 35131 Padova, Italy.
INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova, Italy.
Phys Rev Lett. 2018 Aug 17;121(7):071101. doi: 10.1103/PhysRevLett.121.071101.
We propose a novel framework where light (sub-GeV) dark matter (DM) is detectable with future MeV γ-ray telescopes without conflicting with cosmic microwave background (CMB) data. The stable DM particle χ has a very low thermal relic abundance due to its large pair-annihilation cross section. The DM number density is stored in a slightly heavier, metastable partner ψ with suppressed pair-annihilation rates, that does not perturb the CMB, and whose late-time decays ψ→χ fill the Universe with χ DM particles. We provide explicit, model-independent realizations for this framework, and discuss constraints on late-time decays, and thus on parameters of this setup, from CMB, big bang nucleosynthesis, and large scale structure.
我们提出了一个新的框架，在这个框架中，未来的 MeV γ射线望远镜可以探测到轻（亚GeV）暗物质（DM），而不会与宇宙微波背景（CMB）数据相冲突。由于其大的对湮灭截面，稳定的 DM 粒子 χ 具有非常低的热遗迹丰度。由于对湮灭率受到抑制，DM 数密度存储在一个稍微重一些的、亚稳态的伙伴 ψ 中，它不会干扰 CMB，而其后期的衰变 ψ→χ 则用 χ DM 粒子填充了整个宇宙。我们为这个框架提供了明确的、模型独立的实现，并讨论了来自 CMB、大爆炸核合成和大尺度结构的后期衰变的限制，从而限制了这个设置的参数。
