论文标题
在快速扩张的宇宙中
Secluded Dark Sector and Muon $(g-2)$ in the Light of Fast Expanding Universe
论文作者
论文摘要
大爆炸型杂质合成之前缺乏信息（BBN）使我们可以假设存在一个新物种$ ϕ $，其能量密度红移为$ a^{ - （4+n）} $，其中$ n> 0 $ and $ a $是规模因子。这种非标准的宇宙设置有助于在黑暗和可见扇区之间较大的门户耦合$（ε）$，即使两个部门不处于热平衡状态。 Here, we have considered $U(1)_{L_μ-L_τ}\otimes U(1)_X$ gauge extension of the Standard Model (SM) and studied different phases of the cosmological evolution of a thermally decoupled dark sector such as leak-in, freeze-in, reannihilation, and late-time annihilation in the presence of fast expansion.由于树级的动力学混合在$ u（1）_x $和$ u（1）_ {l_μ-l_τ} $ garuge玻色子中，带有$μ$和$τ$味的sm的黑暗扇区夫妇。我们表明，在我们的情况下，有可能调和暗物质遗物密度和muon $（g-2）$异常。特别是，我们以$ 2 \ times 10^{ - 4} \ Lesssimε\ Lessim 10^{ - 3} $，$ 5.5 {\ rm Mev} \ Lessim m_ {z^\ prime} \ lyssim 200 { M_χ\ Lessim 10 {\ rm tev} $深色物质的遗物密度约束，Muon $（G-2）$异常的约束以及其他宇宙学的，天体物理的约束。
The lack of information before Big Bang Neucleosynthesis (BBN) allow us to assume the presence of a new species $ϕ$ whose energy density redshifts as $a^{-(4+n)}$ where $n>0$ and $a$ is the scale factor. This non-standard cosmological setup facilitates a larger portal coupling $(ε)$ between the dark and the visible sectors even when the two sectors are not in thermal equilibrium. Here, we have considered $U(1)_{L_μ-L_τ}\otimes U(1)_X$ gauge extension of the Standard Model (SM) and studied different phases of the cosmological evolution of a thermally decoupled dark sector such as leak-in, freeze-in, reannihilation, and late-time annihilation in the presence of fast expansion. Due to the tree level kinetic mixing between $U(1)_X$ and $U(1)_{L_μ-L_τ}$ gauge bosons, the dark sector couples with the $μ$ and $τ$ flavored leptons of the SM. We show that in our scenario it is possible to reconcile the dark matter relic density and muon $(g-2)$ anomaly. In particular, we show that for $2\times 10^{-4} \lesssim ε\lesssim 10^{-3}$, $5.5{\rm MeV} \lesssim m_{Z^\prime} \lesssim 200{\rm MeV}$, $n=4$, and $1{\rm TeV} \lesssim m_χ\lesssim 10{\rm TeV}$ relic density constraint of dark matter, constraint from muon $(g-2)$ anomaly, and other cosmological, astrophysical constraints are satisfied.
