Dark Matter from Late Invisible Decays to/of Gravitinos

TL;DR

This paper explores a supersymmetric model where late invisible decays to or from gravitinos can account for all dark matter, while satisfying cosmological constraints and affecting structure formation.

Contribution

It demonstrates that late invisible decays involving gravitinos can produce the entire dark matter relic abundance within viable parameter space.

Findings

Decays produce dark matter candidates consistent with BBN and CMB constraints.

Dark radiation from decays can influence galaxy and Lyman-alpha observations.

Model parameters can explain the total dark matter without conflicting with cosmological data.

Abstract

In this work, we sift a simple supersymmetric framework of late invisible decays to/of the gravitino. We investigate two cases where the gravitino is the lightest supersymmetric particle or the next-to-lightest supersymmetric particle. The next-to-lightest supersymmetric particle decays into two dark matter candidates and has a long lifetime due to gravitationally suppressed interactions. However, because of the absence of any hadronic or electromagnetic products, it satisfies the tight bounds set by big bang nucleosynthesis and cosmic microwaved background. One or both of the dark matter candidates produced in invisible decays can contribute to the amount of dark radiation and suppress perturbations at scales that are being probed by the galaxy power spectrum and the Lyman-alpha forest data. We show that these constraints are satisfied in large regions of the parameter space and, as a result, the late invisible decays to/of the gravitino can be responsible for the entire dark matter relic abundance.