Supersymmetric Leptogenesis with a Light Hidden Sector

TL;DR

This paper introduces a model with a light hidden sector in supersymmetry that resolves conflicts between thermal leptogenesis and primordial nucleosynthesis by diluting the abundance of next-to-lightest supersymmetric particles.

Contribution

It proposes a novel mechanism involving a light hidden sector to reconcile thermal leptogenesis with primordial element abundances in supersymmetric models.

Findings

The hidden sector effectively dilutes supersymmetric particle abundances during nucleosynthesis.

The model is compatible with current cosmological and astrophysical bounds.

Potential experimental signatures include collider signals and cosmic-ray observations.

Abstract

Supersymmetric scenarios incorporating thermal leptogenesis as the origin of the observed matter-antimatter asymmetry generically predict abundances of the primordial elements which are in conflict with observations. In this paper we propose a simple way to circumvent this tension and accommodate naturally thermal leptogenesis and primordial nucleosynthesis. We postulate the existence of a light hidden sector, coupled very weakly to the Minimal Supersymmetric Standard Model, which opens up new decay channels for the next-to-lightest supersymmetric particle, thus diluting its abundance during nucleosynthesis. We present a general model-independent analysis of this mechanism as well as two concrete realizations, and describe the relevant cosmological and astrophysical bounds and implications for this dark matter scenario. Possible experimental signatures at colliders and in cosmic-ray observations are also discussed.