Conversion-Driven Leptogenesis: A Testable Theory of Dark Matter and Baryogenesis at the Electroweak Scale

TL;DR

This paper proposes a testable theory linking dark matter and baryogenesis through conversion-driven leptogenesis at the electroweak scale, predicting observable collider signatures.

Contribution

It introduces a novel conversion-driven leptogenesis mechanism that explains both dark matter relic density and baryon asymmetry within a testable electroweak-scale framework.

Findings

Dark matter masses near the electroweak scale predicted.

Soft displaced leptons as collider signatures.

Mechanism satisfies Sakharov's conditions for baryogenesis.

Abstract

The phenomena of dark matter and the baryon asymmetry pose two of the most pressing questions in today's fundamental physics. Conversion-driven freeze-out has emerged as a successful mechanism to generate the observed dark matter relic density. It supports thermalization of dark matter despite its very weak couplings aligning with the null results from direct and indirect detection experiments. In this letter, we demonstrate that the departure from equilibrium of dark matter, induced by semi-efficient conversions, satisfies Sakharov's conditions, providing a novel explanation for both dark matter and the baryon asymmetry. Specifically, for a leptophilic model, we establish the mechanism of conversion-driven leptogenesis. The scenario predicts dark matter masses close to the electroweak scale offering testable predictions, such as soft displaced leptons at the LHC and future colliders.