Freeze-in Leptogenesis via Dark-Matter Oscillations

TL;DR

This paper explores a novel freeze-in leptogenesis mechanism involving dark-matter oscillations, highlighting its unique features, potential signals, and implications for cosmology and particle physics.

Contribution

It introduces a new leptogenesis model via dark-matter oscillations, analyzing its cosmological viability and experimental testability, with emphasis on flavor effects and model distinctions.

Findings

Lepton flavor effects significantly impact leptogenesis outcomes.

The model predicts new electroweak-charged particles detectable by current experiments.

Enhanced baryon asymmetry compared to sterile neutrino oscillation scenarios.

Abstract

We study the cosmology and phenomenology of freeze-in baryogenesis via dark-matter oscillations, taking the dark matter to couple to Standard Model leptons. We investigate viable models both with and without a $Z_2$ symmetry under which all new fields are charged. Lepton flavor effects are important for leptogenesis in these models, and we identify scenarios in which the baryon asymmetry is parametrically distinct from and enhanced relative to leptogenesis from sterile neutrino oscillations. The models we study predict the existence of new, electroweak-charged fields, and can be tested by a combination of collider searches, structure-formation studies, X-ray observations, and terrestrial low-energy tests.