标题： 以转换驱动的冻结：超越WIMP范式的暗物质起源 显示英文标题

标题： Conversion-driven freeze-out: Dark matter genesis beyond the WIMP paradigm

摘要： 我们考虑与标准模型(SM)耦合非常微弱的暗物质(DM)，使其自湮灭截面远小于典型的截面，$\langle\sigma v\rangle_{\chi\chi} \ll 10^{-26}\mathrm{cm}^3/\mathrm{s}$。在这种情况下，DM的自湮灭对于冻结过程的动力学可以忽略不计，而DM的稀释仅由较重的伴随暗区粒子的有效湮灭驱动，前提是DM与暗区保持化学平衡。这种化学平衡通过转换过程建立，这些过程所需的耦合比湮灭更小才能有效。DM与SM的化学退耦可以通过湮灭的冻结启动，类似于共湮灭情景，或者通过转换过程的冻结启动，导致转换驱动的冻结情景。我们关注后者并讨论其独特的现象学。 显示英文摘要

摘要： We consider dark matter (DM) with very weak couplings to the standard model (SM), such that its self-annihilation cross section is much smaller than the canonical one, $\langle\sigma v\rangle_{\chi\chi} \ll 10^{-26}\mathrm{cm}^3/\mathrm{s}$. In this case DM self-annihilation is negligible for the dynamics of freeze-out and DM dilution is solely driven by efficient annihilation of heavier accompanying dark sector particles provided that DM maintains chemical equilibrium with the dark sector. This chemical equilibrium is established by conversion processes which require much smaller couplings to be efficient than annihilation. The chemical decoupling of DM from the SM can either be initiated by the freeze-out of annihilation, resembling a co-annihilation scenario, or of conversion processes, leading to the scenario of conversion-driven freeze-out. We focus on the latter and discuss its distinct phenomenology.