Direct Detection of the Wino- and Higgsino-like Neutralino Dark Matters at One-Loop Level

Abstract

The neutralino-nucleon (\tildeχ^0-N) scattering is an important process for direct dark matter searches. In this paper we discuss one-loop contributions to the cross section in the wino-like and Higgsino-like LSP cases. The neutralino-nucleon scattering mediated by the Higgs \tildeχ^0\tildeχ^0 and Z\tildeχ^0\tildeχ^0 couplings at tree level is suppressed by the gaugino-Higgsino mixing at tree level when the neutralino is close to a weak eigenstate. The one-loop contribution to the cross section, generated by the gauge interaction, is not suppressed by any SUSY particle mass or mixing in the wino- and Higgsino-like LSP cases. It may significantly alter the total cross section when σ_{\tildeχ^0 N}\sim 10^{-45} cm^2 or less.

26 pages, 9 figures. Version to be published in Physical Review D