Successful Supersymmetric Dark Matter with Thermal Over/Under-Abundance from Late Decay of a Visible Sector Scalar

TL;DR

This paper introduces a model where a TeV-scale scalar decay in the visible sector explains non-thermal dark matter relic abundance, addressing over/underproduction issues and baryon asymmetry.

Contribution

It proposes a novel decay mechanism involving a visible sector scalar to produce dark matter and baryon asymmetry, improving over previous modulus decay models.

Findings

Correct relic abundance achieved for various annihilation rates

Suppressed gravitino production due to visible sector decay

Potential explanation for baryon-dark matter coincidence

Abstract

We present an explicit model where the decay of an R-parity even scalar $S$ with ${\cal O}({\rm TeV})$ mass is the origin of non-thermal dark matter. The correct relic abundance can be produced for both large and small annihilation rates in accordance with the Fermi constraints on the annihilation cross-section. This scenario has advantages over that of non-thermal dark matter from modulus decay. First, branching ratio for production of R-parity odd particles can be made quite small by a combination of $S$ couplings to matter fields and kinematic suppression, enabling us to obtain the observed dark matter relic density in cases of thermal underproduction as well as overproduction. Second, gravitino production is naturally suppressed by the virtue of decaying scalar belonging to the visible sector. The decaying scalar $S$ can also successfully generate baryon asymmetry of the universe, and may provide an explanation for the baryon-dark matter coincidence puzzle.