Seminar: ‘Dark Sector Karaoke: A 3D EFT for a Pitch-Perfect Phase Transition’

Speaker: Cristina Puchades Ibáñez (University of Mainz)

Venue & Time: Red Room / 15:00

Abstract: We explore the dynamics of cosmological phase transitions in a dark sector model featuring a dark photon associated with a U(1)D gauge symmetry and radiative symmetry breaking. Our analysis focuses on different approaches to construct the effective potential: the high-temperature approximation, a full numerical evaluation of the thermal integrals, and a dimensionally reduced 3D effective theory built with DRalgo, at both leading and next-to-leading order. We as well explore the effect of including the running of the parameters in order to respect the hiercarchy scales. We investigate how these methods impact the characterization of the phase transition, particularly in the supercooled regime. Our results show the importance of method choice when predicting observable signatures, and establish a benchmark for future studies of first-order phase transitions in models with weakly coupled dark sectors.