论文标题
$ \ mathbf {{n} _ {eff}} $来自激动的dm状态
$\mathbf{{N}_{eff}}$ from Excited DM state
论文作者
论文摘要
对于源自共同灭绝过程的冷暗物质（DM），在黑暗部门将有激动的状态，该状态可能在冻结后不久就会腐烂或消灭。在本文中，我们研究了这些激发态衰变对有效中微子物种数量的影响，即$ n _ {\ rm eff}^{} $，这是一个重要的宇宙学参数，将由未来的CMB-S4项目测试。我们通过Higgs门户在伪DIRAC DM模式的框架中工作。计算了DM的遗物密度和直接检测信号，这给出了可用的参数空间。激发态的影响（伪dirac fermion的重成分）对活性中微子的解耦，通过求解由激发态衰减引起的碰撞期限的光子和中微子的玻尔兹曼方程来研究活性中微子。数值结果表明$ | n _ {\ rm eff}^{} | $可以是$ 10^{ - 4} $的顺序，这取决于激发的DM状态的质量和寿命。
For a cold dark matter (DM) originating from the co-annihilation processes, there will be excited state(s) in the dark sector, that may decay or annihilate away shortly after their freeze-out. In this paper we investigate the impact of the decay of these excited states on the effective number of neutrino species, $N_{\rm eff}^{}$, which is an important cosmological parameter and will be tested by the future CMB-S4 project. We work in the framework of pseudo-Dirac DM mode via the Higgs portal. The relic density and the direct detection signal of the DM are calculated, which gives the available parameter space. Impacts of the excited state (the heavy component of the pseudo-Dirac fermion) on the decoupling of active neutrinos are investigated by solving Boltzmann equations of photon and neutrinos with collision term induced by the decay of the excited state. The numerical result shows that $|N_{\rm eff}^{}|$ can be of the order $10^{-4}$, which depends on the mass and lifetime of excited DM state.
