The Lower Bound on the Neutralino-Nucleon Cross Section

Abstract

We examine if there is a lower bound on the direct detection cross section for the neutralino dark matter in the MSSM. If we impose the minimal supergravity boundary conditions as well as the &#34;naturalness&#34; condition, in particular m_{1/2} < 300 GeV, we show that there is a lower bound of 10^{-46}cm^2 on the cross section for neutralino scattering off of a proton. We also clarify the origin for the lower bound. Relaxing either of the assumptions, however, can lead to much smaller cross sections.