XENON100 Implications for Naturalness in the MSSM, NMSSM and lambda-SUSY

In a recent paper arXiv:1107.5048, we discussed the correlation between the elastic neutralino-nucleon scattering cross section, constrained by dark matter direct detection experiments, and fine-tuning at tree-level in the electroweak symmetry breaking sector of the Minimal Supersymmetric Standard Model (MSSM). Here, we show that the correlation persists in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), and its variant, lambda-SUSY. Both models are strongly motivated by the recent discovery of a 125 GeV Higgs-like particle. We also discuss the implications of the recently published bound on the direct detection cross section from 225 live days of XENON100 experiment. In both the MSSM and the NMSSM, most of the parameter space with fine-tuning less than 10% is inconsistent with the XENON100 bound. In lambda-SUSY, on the other hand, large regions of completely natural electroweak symmetry breaking are still allowed, primarily due to a parametric suppression of fine-tuning with large \lambda. The upcoming XENON1T experiment will be able to probe most of the parameter space with less than 1% fine-tuning in all three models.