论文标题
宇宙学和对撞机的无菌中微子门户暗物质的闪闪发光
Shinning Light on Sterile Neutrino Portal Dark Matter from Cosmology and Collider
论文作者
论文摘要
如果深色扇区由深色标量$ ϕ $和深色费米昂$χ$组成，那么在精确的$ z_2 $对称下，无菌中微子$ n $可以用作黑暗扇区和标准模型之间的使者，这是通过yukawa耦合$λ_{ds}} {ds}} \ bar的。在本文中，我们专注于特定方案$ m_n> m_ϕ+m_χ$，而$χ$是fibl dark Matter。 Yukawa耦合$λ_{ds} $和混合角度$θ$的较小度，深度标量$ ϕ $的衰减宽度被双重抑制。延迟的衰减$ ϕ \toχν$将对宇宙学可观察物产生很大的影响，例如大爆炸核合成，宇宙微波背景各向异性动力谱，相对性中微子的有效数量$ n _ _ {\ rm fef} $ and eneprinotialitrino中性中性中性中微子。同时，无菌中微子可以在$ m_n <m_w $ $ m_n时在山口上产生流离失所的顶点签名。深色标量$ ϕ $还将引起可测量的希格斯隐形衰减，以实现相对较大的四分之一耦合。本文对宇宙学和对撞机的约束进行了全面分析。我们发现，几乎$ m_n <m_w $的整个参数空间都在未来实验的范围内。
Provided the dark sector consisted of a dark scalar $ϕ$ and a dark fermion $χ$ under an exact $Z_2$ symmetry, the sterile neutrino $N$ can act as the messenger between the dark sector and standard model via the Yukawa coupling $λ_{ds} \barχϕN$. In this paper, we focus on the specific scenario $m_N>m_ϕ+m_χ$ with $χ$ being a FIMP dark matter. The decay width of dark scalar $ϕ$ is doubly suppressed by the smallness of Yukawa coupling $λ_{ds}$ and mixing angle $θ$. The delayed decay $ϕ\toχν$ will have a great impact on cosmological observables such as the Big Bang Nucleosynthesis, the Cosmic Microwave Background anisotropy power spectra, the effective number of relativistic neutrino species $N_{\rm eff}$ and the energetic neutrino flux. Meanwhile, the sterile neutrino can generate displaced vertex signature at colliders when $m_N<m_W$. The dark scalar $ϕ$ will also induce measurable Higgs invisible decay for relatively large quartic coupling. A comprehensive analysis of constraints from cosmology and collider is performed in this paper. We find that almost the whole parameter space with $m_N<m_W$ is under the reach of future experiments.
