SD and SI signals, which has recently been explored in [15–18]. In the next section, we begin by discussing the current experimental status and then make naive estimates for the SI and SD DD cross sections from h and Z 0 exchange respectively. In Sec. III we lay out the specific structure of the SI and SD operators in the MSSM and estimate the naive size of the SI and SD cross sections. Then in Sec. IV we review the argument for a well-tempered neutralino and discuss some alternatives. Sec. V concentrates on illuminating the expected size of the SD cross section for mixed DM models with various restrictions. In Sec. VI we describe the conditions under which SI and SD signals in the MSSM are expected to be correlated. Technical results are relegated to three appendices. The interactions in Eqs. (3) and (4) lead to SI and SD elastic signals in DD experiments, respectively. In Fig. 1 we have plotted the current experimental limits for SI and SD DD. Currently, the state of the art SI experiments are CDMS [19] and XENON [20]. XENON constrains σ χ p SI < 4 . 5 × 10 − 8 pb for m$_{χ}$ = 30 GeV. After combining their most recent run with previous data, CDMS-II has a 90% CL bound of 3.8 × 10 − 8 pb for a WIMP with a mass of 70 GeV [21]. In the most recent data set, two tantalizing events were seen, but it is premature to attribute these to signal. In any case, XENON100 expects to place a limit on the order of σ χ p SI ≈ few × 10 − 9 pb by early 2010. Thus, we will consider SI cross sections greater than 5 × 10 − 9 pb as potentially probeable in the short-term, and hence “large.” There are two ways the SD cross sections are constrained. The first is via DD experiments. The current best bound on the SD DM-proton interaction comes from the KIMS experiment [22], σ χ p SD < 1 . 6 × 10 − 1 pb for m$_{χ}$ = 70 GeV; the best bound on the SD DM-neutron interaction coming from the XENON experiment, σ χ n SD < 6 × 10 − 3 pb for m$_{χ}$ = 20 GeV, with the strongest bounds for masses of O (10) GeV coming from PICASSO [23]. There are also bounds from DM capture in the sun, assuming (as is the case in the MSSM) that the DM has annihilation products which give rise to relatively hard neutrinos. Assuming annihilation of the DM to W ± bosons is appreciable (as is appropriate for much of the parameter space considered here, see Sec. IV), IceCube [24] places very strong bounds for masses above 250 GeV with the strongest bounds coming at 250 GeV, σ χ p SD < 3 × 10 − 4 pb. At present, no limits exist from IceCube below this mass. For smaller masses, the best limits of this type come from SuperK [25], σ χ p SD < 10 − 2 pb above m$_{χ}$ > 20 GeV. Perhaps within the next two years [26], the COUPP [27] and PICASSO [28] experiments will take data with a projected sensitivity to SD scattering of σ χ p SD ≈ 10 − 4 pb. They will also have sensitivity down to much lower masses than the neutrino experiments. The XENON 4 II. DIRECT DETECTION PRELIMINARIES