论文标题
用规模不变的鱼探测前BBN时代
Probing pre-BBN era with Scale Invariant FIMP
论文作者
论文摘要
由于涉及的耦合的较小，在实验室中检测到暗物质（DM）遗物很难在实验室中进行。但是，在大爆炸核合成之前（BBN）之前，宇宙的非标准宇宙学历史可以极大地改变这种情况。在这种情况下，我们研究了标准模型（SM）的经典规模不变$ u（1）_x $量规扩展的暗物质的冻结生产，最近被称为\ textit {scale vextit {scale formiant fimbirace}。我们假设一个附加物种在早期占主导地位的宇宙的能量密度，从而导致在给定温度下的膨胀速率大于标准辐射主导的情况下的膨胀率。 We find, the \textit{out-of-equilibrium} scattering processes involving particles in the thermal bath lead to significantly suppressed DM production in this era, thereby enhancing the couplings between the visible and the dark sector (by several orders of magnitude) to satisfy the observed DM abundance, and improving the detection prospects for freeze-in in turn.基础理论的比例不变性在模型中仅留下四个免费参数：DM质量$ m_x $，量规耦合$ g_x $，从早期标量为辐射为主导的ERA的过渡温度$ T_R $以及该温度的PowerLaw依赖$ N $。我们在这种最小的设置中显示了Faser，Mathusla，Dune，Ship等实验将根据$ \ {n，\，T_R \} $的选择来探测各种宇宙学模型，这些模型也满足了Planck观察到的Relic Mentive Bond。此外，由于存在自然光标度介体，在Xenon1t，Pandax-4t或Xenonnt上直接检测DM与Higgs-Scalar混合$ \sinθ\ simeq \ simeq \ {10^{ - 5} { - 5} -10^{-110^{ - 3} $ cromenty nor-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In-In- BBN时代。
Detecting dark matter (DM) relic via freeze-in is difficult in laboratories due to smallness of the couplings involved. However, a non-standard cosmological history of the Universe, prior to Big Bang Nucleosynthesis (BBN), can dramatically change this scenario. In this context, we study the freeze-in production of dark matter in classically scale invariant $U(1)_X$ gauge extension of the Standard Model (SM), recently dubbed as the \textit{Scale Invariant FIMP Miracle}. We assume an additional species dominates the energy density of the Universe at early times, causing the expansion rate at a given temperature to be larger than that in the standard radiation-dominated case. We find, the \textit{out-of-equilibrium} scattering processes involving particles in the thermal bath lead to significantly suppressed DM production in this era, thereby enhancing the couplings between the visible and the dark sector (by several orders of magnitude) to satisfy the observed DM abundance, and improving the detection prospects for freeze-in in turn. Scale invariance of the underlying theory leaves only four free parameters in the model: the DM mass $m_X$, the gauge coupling $g_X$, the temperature of transition $T_R$ from early scalar-dominated to radiation-dominated era and the power-law dependence $n$ of this temperature. We show, within this minimal set-up, experiments like FASER, MATHUSLA, DUNE, SHiP will be probing various cosmological models depending on the choice of $\{n,\,T_R\}$ that also satisfy the PLANCK observed relic density bound. Moreover, due to the presence of a naturally light scalar mediator, the direct detection of the DM at XENON1T, PandaX-4T or XENONnT becomes relevant for Higgs-scalar mixing $\sinθ\simeq\{10^{-5}-10^{-3}\}$, thus providing complementary probes for freeze-in, as well as for non-standard cosmological pre-BBN era.
