科研之友
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摘要
We explore the dark matter sector in extensions of the minimal supersymmetric standard model that can provide a good fit to the PAMELA cosmic-ray positron excess, while at the same time addressing the little-hierarchy problem of the minimal supersymmetric standard model. Adding a singlet Higgs super-field S can account for the observed positron excess, as recently discussed in the literature, but we point out that it requires a fine-tuned choice for the parameters of the model. We find that including an additional singlet Psi in a model with gauge-mediated supersymmetry breaking is a minimal extension which allows both a reduction of the weak-scale fine-tuning and an interpretation of the cosmic-ray observations in terms of dark matter annihilations in the galactic halo. Our setup contains a light axion but does not require light CP-even scalars in the spectrum.
- 出版日期2010-8-30
