  The requirement that the MSSM remain an acceptable effective field theory up
to energies beyond the weak scale constrains the sparticle spectrum, and hence
the permissible ranges of cold dark matter neutralino-proton cross sections.
Specifically, squarks are generally much heavier than sleptons if no tachyons
are to appear before the GUT scale ~10^16 GeV, or even before 10 TeV. We
display explicitly the allowed ranges of effective squark and slepton masses at
the weak scale, and the cross-section ranges allowed if the MSSM is to remain
valid without tachyons up to 10 TeV or the GUT scale. The allowed areas in the
cross section-mass plane for both spin-independent and spin-dependent
scattering are significantly smaller than would be allowed if the MSSM were
required to be valid only around the weak scale. In addition to a reduction in
the maximum cross section, the upper limit on the neutralino mass is greatly
reduced when tachyons are avoided, particularly for smaller values of the
squark masses.
