Impact of Cosmological Phase Transitions on Dark Matter Phenomenology

随着电弱尺度暗物质(DM)继续顽固地逃避实验探测，宇宙中DM丰度不是由热冻结决定的可能性，而是由某种替代机制决定的可能性，变得越来越吸引人。我们建议在这里特别研究一些新颖的场景，在这些场景中，早期宇宙中的DM的动力学，以及它今天的丰度，都受到宇宙学相变的影响。标量场的真空期望值(VEV)会在相变期间发生突变，从而破坏或恢复稳定DM粒子的对称性。此外，通过影响粒子质量，标量场VEV可以确定在运动学上是否允许DM衰变或湮灭过程。在初步的原则性研究的基础上，我们计划开发实现这一机制的理论模型来设定Dm丰度，并在地球、天体物理和宇宙学实验中探索它们的现象学。此外，我们计划通过利用所考虑的场景通常具有强烈的一级相变这一事实，将DM现象学与电弱重子发生联系起来。最后，我们计划研究早期宇宙中DM现象学和相变引力波信号之间的相互作用。

As electroweak-scale dark matter (DM) continues to stubbornly evade experimental detection, the possibility that the DM abundance in the Universe is not determined by thermal freeze-out, but by some alternative mechanism, is becoming more and more appealing. We propose here to investigate in particular novel scenarios in which the dynamics of DM in the early Universe, and thus its abundance today, is influenced by cosmological phase transitions. The vacuum expectation values (vevs) of scalar fields can change abruptly during a phase transition, thereby breaking or restoring the symmetry that stabilizes DM particles. Moreover, by affecting particle masses, scalar field vevs can determine whether or not DM decay or annihilation processes are kinematically allowed. Based on a preliminary proof-of-principle study, we plan to develop theoretical models implementing this mechanism for setting the DM abundance,and to explore their phenomenology in terrestrial, astrophysical, and cosmological experiments. Moreover, we plan to connect DM phenomenology to electroweak baryogenesis by exploiting the fact that the scenarios under consideration often feature strong first order phase transitions. Finally, we plan to study the interplay between DM phenomenology and the gravitational wave signals of phase transitions in the early Universe.