Speaker: Cash Hauptmann, University of Nebraska–Lincoln
Abstract: I will discuss ongoing work concerning cosmological phase transitions (PTs) and their possible roles in the production of dark matter (DM) and primordial black holes (PBHs). For DM, I have recently proposed a non-thermal production mechanism utilizing supercooled first-order PTs which can enhance the abundance of DM. This enhancement opens the viable DM parameter space to models with higher annihilation cross sections which would have otherwise produced too little DM in the standard thermal scenario. Another interesting consequence of first-order PTs could be an efficient trapping of DM in false vacuum domains, and their subsequent collapse to PBHs. Depending on the energy scale of the PT, these PBHs could make up significant fractions (if not all) of today’s DM abundance. Whatever their byproducts may be, first-order PTs are expected to source stochastic background signals of gravitational waves—potentially probeable by next-generation detectors. With this in mind, all phenomenological results are presented in a robust multi-messenger fashion; correlating DM or PBH constraints with gravitational wave signals.