Fine-Tuning Implications of Direct Dark Matter Searches in the MSSM

Understand

We study theoretical implications of direct dark matter searches in the minimal supersymmetric standard model (MSSM).

• We assume that no accidental cancellations occur in the spin-independent elastic neutralino-quark scattering cross section, but do not impose any relations among the weak-scale MSSM parameters.
• We show that direct detection cross section below 10^-44 cm^2 requires the lightest supersymmetric particle (LSP) neutralino to be close to either a pure gaugino or pure Higgsino limit, with smaller cross sections correlated with smaller admixture of the subdominant components.
• The current XENON100 bound rules out essentially all models in which the lightest neutralino has the Higgsino fraction between 0.2 and 0.8.