Speaker
Dr
Krzysztof Turzynski
(University of Warsaw)
Description
Supersymmetry breaking mediated by gauge interactions is regarded an attractive option due to the lack of new sources of flavor changing neutral currents other than those already present in the Standard Model. In models with gauge mediated supersymmetry breaking (GMSB), the dark matter particle is the gravitino. It is produced both thermally in scatterings in the hot plasma and non-thermally from decays of the next to lightest supersymmetric particle (NLSP). If the NLSP is sufficiently abundant during Big Bang Nucleosynthesis (BBN), these decays can alter the abundances of light elements. This, in turn, gives constraints on the gravitino mass and, for the observed dark matter abundance, on the reheating temperature of the Universe. Since sufficiently high reheating temperature is crucial for thermal leptogenesis, one obtains constraints on viable models with GMSB.
We study the interplay of these constraints for a neutralino NLSP with a GeV-scale gravitino in the phenomenological MSSM, without any particular mass relations between sparticles. We identify the sparticle spectra for which the NLSP relic abundance is sufficiently small to avoid conflict with primordial nucleosythesis, but the relic abundance of the gravitinos is consistent with a reheating temperature allowing for thermal leptogenesis. This is possible e.g. in a scenario with bino-gluino mass degeneracy, in which there are strong coannihilations. We also briefly discuss the consequences of such NLSP-gluino mass degeneracy for the prospects of discovering supersymmetry at the LHC.
Primary author
Dr
Krzysztof Turzynski
(University of Warsaw)
Co-authors
Prof.
James D. Wells
(University of Michigan and CERN)
Dr
Laura Covi
(DESY)
Prof.
Marek Olechowski
(University of Warsaw)
Prof.
Stefan Pokorski
(University of Warsaw)
