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A keV-scale gravitino arsing from a minimal supersymmetric (SUSY) Standard Model (MSSM) is an interesting possibility since the small scale problems that $Lambda$CDM model encounters in the modern cosmology could be alleviated with the keV-scale gravitino serving as the warm dark matter (WDM). Such a light gravitino asks for a low scale supersymmetry (SUSY) breaking for which the gauge mediation (GM) is required as a consistent SUSY-breaking mediation mechanism. In this paper, we show upperbounds of the masses of the second CP-even Higgs boson $H$ and the CP-odd Higgs boson $A$, assuming the keV-scale gravitino to be responsible for the current DM relic abundance: the upperbound on the mass of $H/A$ is found to be $sim 4$ TeV for the gravitino mass of $mathcal{O}(10$-$100)$ keV. Interestingly, the mass of $H/A$ can be as small as 2-3 TeV and the predicted $tanbeta$ is as large as 55-60 for the gravitino mass of $mathcal{O}(10)$ keV. This will be tested in the near future Large Hadron Collider (LHC) experiments.
We present an inflationary scenario based on a phenomenologically viable model with direct gauge mediation of low-scale supersymmetry breaking. Inflation can occur in the supersymmetry-breaking hidden sector. Although the reheating temperature from t
We reinvestigate the scenario that the amount of the baryons and the gravitino dark matter is naturally explained by the decay of the Q balls in the gauge-mediated SUSY breaking. Equipped by the more correct decay rates into gravitinos and baryons re
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We propose a new non-thermal mechanism of dark matter production based on vacuum misalignment. A global $X$-charge asymmetry is generated at high temperatures, under which both the will-be Higgs and the dark matter are charged. At lower energies, the
We study an Abelian gauge extension of the standard model with fermion families having non-universal gauge charges. The gauge charges and scalar content are chosen in such an anomaly-free way that only the third generation fermions receive Dirac mass