Leptogenesis via bubble collisions
Martina Cataldi, Bibhushan Shakya
Abstract
Abstract We present a novel realization of leptogenesis from the decays of sterile (right-handed) neutrinos (RHNs) produced from runaway bubble collisions at a first order phase transition. Such configurations can produce heavy RHNs with mass many orders of magnitude above the scale of symmetry breaking as well as the temperature of the plasma, thereby enabling high scale leptogenesis without the need for high reheat temperatures while also naturally suppressing washout effects. This mechanism is also efficient for RHN masses ≳ 10 14 GeV, the natural scale for type-I seesaw with 𝒪 (1) couplings, where standard thermal leptogenesis faces strong suppression from washout processes in equilibrium. The corresponding phase transitions are at scales ≳ 10 9 GeV and produce gravitational wave signals that could be detected by future experiments.