Blind Spots for neutralino Dark Matter in the MSSM with an intermediate m_A

Understand

We study the spin-independent neutralino Dark Matter scattering off heavy nuclei in the MSSM.

• We identify analytically the blind spots in direct detection for intermediate values of $m_A$.
• In the region where $\mu$ and $M_{1,2}$ have opposite signs, there is not only a reduction of the lightest CP-even Higgs coupling to neutralinos, but also a destructive interference between the neutralino scattering through the exchange of the lightest CP-even Higgs and that through the exchange of the heaviest CP-even Higgs.
• At critical values of $m_A$, the tree-level contribution from the light Higgs exchange cancels the contribution from the heavy Higgs, so the scattering cross section vanishes.