Baryogenesis via relativistic bubble expansion

Iason Baldes, Simone Blasi, Alberto Mariotti, Alexander Sevrin, Kevin Turbang, Alexandre Sevrin

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We present a novel baryogenesis mechanism in which the asymmetry is sourced from heavy particles which either gain their mass or are created during bubble expansion in a strong first order phase transition. These particles then decay in a CP and baryon number violating way inside the bubble. The particles are inherently out-of-equilibrium and sufficiently dilute after wall crossing so the third Sakharov condition is easily met. Washout is avoided provided the reheat temperature is sufficiently below the scale of the heavy particles. The mechanism relies on moderate supercooling and relativistic walls which -- in contrast to electroweak baryogenesis -- generically leads to a sizable gravitational wave signal, although in the simplest realisations at frequencies beyond upcoming detectors. We present a simple example model and discuss the restrictions on the parameter space for the mechanism to be successful. We find that high reheat temperatures $T_{\rm RH} \gtrsim 10^{10}$ GeV are generally preferred, whereas stronger supercooling allows for temperatures as low as $T_{\rm RH} \sim 10^{6}$ GeV, provided the vacuum energy density is sufficiently suppressed. We briefly comment on using resonantly enhanced CP violation to achieve even lower scales.
Original language English 115029 24 Physical Review D 104 11 https://doi.org/10.1103/PhysRevD.104.115029 Published - 28 Dec 2021

Bibliographical note

22 pages, 8 figures. V2: accepted for publication in PRD

• hep-ph

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• SRP8: Strategic Research Programme: High-Energy Physics at the VUB

1/11/1231/10/22

Project: Fundamental