New Contributions to Neutralino Elastic Cross-sections from CP Violating Phases in the MSSM

Abstract

We compute the four-Fermi neutralino-quark interaction Lagrangian including contributions from the CP violating phases in the MSSM. We find that neutralino-nucleus scattering cross-sections relevant for direct detection experiments show a strong dependence on the value of the CP-violating phase associated with the $\mu$ parameter, ${\theta }_{\mu }$. In some cases, for a broad range of non-zero ${\theta }_{\mu }$, there are cancellations in the cross-sections which reduce the cross-section by more than an order of magnitude. In other cases, there may be enhancements as one varies ${\theta }_{\mu }$.

Comments: 9 pages in LaTeX, 5 eps figures; corrected error in spin-independent cross-section, figures modified, conclusions unchanged