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The dark matter as a light gravitino

Gilbert Moultaka (Laboratory of Theoretical and Astroparticle Physics- university of Montpellier & CNRS, FRANCE)
05 July 2007, 14:15 - 16:00

In gauge mediated supersymmetry breaking models the relatively light messenger and/or secluded sectors can be partly present in the early universe, depending on the value of the reheat temperature. In particular, a relic stable lightest messenger scalar field with a mass greater than a few tens of TeV would typically lead to an overcloser problem. Relying on a recently studied scenario in the context of a (supergravity coupled) unifying $SO(10)$ gauge group, where a solution to this problem can yield cold dark matter light gravitinos even for a very high reheat temperature, we calculate the full one-loop induced lightest messenger annihilation into a pair of gluons, which is the leading process in the determination of the relic abundance of this MSSM singlet messenger. We also analyze, in terms of the messenger and spurion parameters, the ensuing gravitino abundance due to entropy dilution, assuming Planck scale reduced messenger decay into MSSM particles as well as thermal and non-thermal gravitino production. [based on Phys.Lett.B645:222-227,2007, Phys.Rev.D73:043514,2006, JCAP 0607:010,2006]
Moultaka.pdf [428 KBytes]