the SD coupling vanishes. Instead, the Higgsino forms a Dirac state, and the large vector scattering of the Dirac neutrino is recovered. Hence, mixing with ˜ B and/or ˜ W (so that | Z$_{H}$$_{u}$ | ̸ = | Z$_{H}$$_{d}$ | ) is required in order for the d$_{q}$ ’s to be non-zero. This requirement also implies a non-zero SI cross section, giving the correlation demonstrated below. The typical cross section for SD DD in the MSSM (again see Sec. IV) is given by There are reasons to expect the squarks do not make a sizable contribution to the DD cross sections. In the MSSM, satisfying the LEP bound on the Higgs boson mass requires large radiative corrections from the stop loops. This implies that at least one stop must have a TeV scale mass. Renormalization group flow tends to make the third generation sparticles lighter than the partners for the first and second generations. Therefore, it is plausible that squark contributions to DD scattering are negligible since only the first and second generation squarks contribute (see Appendix A for details about squark exchange). For concreteness, in all scans below we take the scalar superparters to be O (2 TeV). This is also why Eqs. (23) and (25) are expected to be good approximations. For a study which focuses on the effects of light squarks, see [16]. Arkani-Hamed, Delgado and Giudice [9] argued that when one takes the LEP limits on charginos and sleptons into account, a pure neutralino ( i.e. composed of only one gaugino eigenstate, usually taken to be Bino) is no longer the “natural” MSSM DM candidate, at least when one imposes the requirement of a thermal cosmology. They claim that one should instead consider a mixed neutralino, which they have dubbed “well-tempered.” Since the relic density of mixed DM is set by annihilations to W $^{+}$W − (and t ¯ t when kinematically allowed) there is a further condition that m$_{χ}$ > m$_{W}$ . Hence, we will impose this requirement when we refer to “thermal” DM in the analysis that follows. In what follows, we review their argument and then discuss some non-thermal options. Note that SI DD has previously been studied for well-tempered models [38, 39], but no dedicated SD study exists. IV. THE ARGUMENT FOR A WELL-TEMPERED NEUTRALINO σ MSSM SD ( χ p → χ p ) ≈ 4 × 10 − $^{4}$pb$^{(}$ | Z$_{H}$$_{d}$ | 2 − | Z$_{H}$$_{u}$ | 2 0 . 1 ) 2 (MSSM: SD typical) . (25) 10