Freiburg 2008 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 16: Beyond the Standard Model (Theorie) II
T 16.9: Vortrag
Dienstag, 4. März 2008, 18:45–19:00, KGI-HS 1021
Indirect Detection of Gravitino Dark Matter with Broken R-parity — •David Tran1 and Alejandro Ibarra2 — 1Universität Hamburg — 2DESY Hamburg
The gravitino is an interesting candidate for the cold dark matter of the Universe in models that predict it to be the lightest supersymmetric particle. However, the next-to-lightest supersymmetric particle may cause cosmological problems with big bang nucleosynthesis, unless a slight violation of R-parity is assumed. This non-conservation of R-parity makes the gravitino unstable. It remains a viable dark matter candidate, however, since the required smallness of the R-parity breaking and a suppression by the Planck mass result in gravitino lifetimes that are much longer than the age of the Universe. The instability of the gravitino also opens up the possibility of its indirect detection, as the decay products from gravitino decay might be observable in present and future experiments. The predicted fluxes have interesting qualititative features and may possibly account for observed excesses in both the gamma-ray and the positron spectra.