Dark matter from late invisible decays to and of gravitinos
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2015 American Physical Society. In this work, we sift a simple supersymmetric framework of late invisible decays to and of the gravitino. We study a simple extension of the minimal supersymmetric standard model that includes isosinglet color-triplet superfields and a singlet superfield. 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 the cosmic microwave 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 and of the gravitino can be responsible for the entire dark matter relic abundance.