论文标题
当冻结由于非玻璃体抑制而发生冻结时：堕落的黑暗扇区的研究
When Freeze-out occurs due to a non-Boltzmann suppression: A study of degenerate dark sector
论文作者
论文摘要
在暗物质的数量密度中，指数抑制或通常称为玻尔兹曼抑制是在通常的热冷冻输出之前产生化学失衡的关键成分。退化/准排级黑暗扇区可以在数量密度上经历不同的指数抑制，类似于放射性衰减定律，从而导致暗物质的延迟冻结机制被称为共同付费的暗物质。在这项工作中，我们研究了隐藏的u $（1）_ {x} $扩展标准模型中的多组分暗物质的动力学。我们通过求解四个耦合的玻尔兹曼方程，计算通过共同付费机制冻结的暗物质的遗物密度。我们证明了由于所有类型的$ 3 \ rightarrow 2 $和$ 2 \ rightarrow 2 $互动以及宇宙的永恒扩展，因此黑暗扇区的温度$ t^\ prime $如何变化。我们发现，$ 3 \ rightarrow 2 $交互作用通过在黑暗部门产生能量的颗粒来增强$ t^\ prime $，而多余的热量则以$ 2 \ rightarrow 2 $互动传递到整个黑暗部门。由于只有通过微弱的门户耦合才能进行直接检测，因此我们通过一个步骤级联过程研究中微子和$γ$ ray的信号，并将我们的结果与超级kamiokande的大气中微子的结果进行了比较，并通过fermi-lat-lat-lat-lat-lat-latection，egreoration，egreoration，egreoration，nectection $ kamiokande和diffuse $γ$。我们发现，目前的情况很容易从大气中微子和散射$γ$ - 射线的观测值中逃脱出所有现有的界限。但是，限制对于准退化方案很重要。
Exponential suppression or commonly known as the Boltzmann suppression in the number density of dark matter is the key ingredient for creating chemical imbalance prior to the usual thermal freeze-out. A degenerate/quasi-degenerate dark sector can experience a different exponential suppression in the number density analogous to the radioactive decay law leading to a delayed freeze-out mechanism of dark matter known as the co-decaying dark matter. In this work, we study the dynamics of a multicomponent dark matter from thermally decoupled degenerate dark sector in a hidden U$(1)_{X}$ extension of the Standard Model. We compute the relic density of dark matter frozen-out through the co-decaying mechanism by solving four coupled Boltzmann equations. We demonstrate how temperature $T^\prime $ of the dark sector changes due to all types of $3\rightarrow 2$ and $2\rightarrow 2$ interactions along with the eternal expansion of the Universe. We find that $3\rightarrow 2$ interactions enhance $T^\prime$ by producing energetic particles in the dark sector while the excess heat is transferred by $2\rightarrow 2$ interactions to the entire dark sector. As the direct detection is possible only through the feeble portal couplings, we investigate the neutrino and $γ$-ray signals from dark matter annihilation via one step cascade processes and compare our results with the measured fluxes of atmospheric neutrinos by Super-Kamiokande and diffuse $γ$-rays by Fermi-LAT, EGRET, INTEGRAL collaborations. We find that the present scenario easily evades all the existing bounds from atmospheric neutrino and diffuse $γ$-ray observations for degenerate dark sector. However, the constraints are significant for quasi degenerate scenario.
