Leptogenesis Assisted by Bubbles

Leptogenesis is an attractive explanation for the observed baryon asymmetry of our Universe. In these proceedings, we study a framework where thermal leptogenesis occurs during a period of a first-order phase transition (FOPT). Right-handed neutrinos (RHNs) remain massless until bubble nucleation. Their abrupt mass generation leads to rapid decoupling and modifies the usual washout dynamics. Compared to standard thermal leptogenesis, where successful asymmetry requires masses above a certain scale, we find that bubble dynamics can dramatically reduce this scale and also study associated gravitational wave signals observable at terrestrial interferometers. Abstract Published by the Jagiellonian University 2026 authors