Acknowledgments Appendix A: Squark Contributions to Direct Detection 3 If exceptionally large left-right in the squark sector is allowed (perhaps through abnormally large a -terms) a contribution to σ$_{SI}$ ( χ N → χ N ) of O (10 − 3 pb) may be obtained. This is typically subdominant to the Z 0 contribution to SD DD. Thus, we will focus on the effects of Z 0 exchange in our discussions of the expected SD cross section. The maximum σ$_{SD}$ ( χ p → χ p ) contribution from squark exchange is for a “left-handed” up-type squark coupling to a pure Wino, due to the larger SU (2) gauge coupling: for a Bino-Wino mix. This is subdominant to the Higgs boson exchange contribution barring the cancellations discussed in Sec. VI D $^{3}$. If one makes the standard assumption that left-right squark mixing ( i.e. a -terms) are proportional to Yukawa couplings, then the squark mixing angle is proportional to m$_{q}$/ ˜ m$_{q}$ . Therefore, all SI couplings will be proportional to a quark mass and there is no enhancement for the light squarks over Higgs boson exchange. The maximum cross section is A non-zero “left-right” squark mixture is required since SI scattering converts a left-handed quark into a right-handed quark. Though a Bino/Wino mixture maximizes the coupling between the quarks and the neutralino, the scattering cross section for a pure Bino is of the same order. The neutralino can scatter off of quarks via s -channel squark exchange, giving contributions to O SI q or O SD q . Only squarks that couple to the light quarks ( u, d, s ) will be able to contribute to the SI and SD cross sections since only the light quarks have non-negligible nuclear matrix elements. We thank Daniel Feldman, Gordy Kane, Eric Kuflik, Ilan Levine and Jure Zupan for useful discussions. The work of T.C. was supported in part by the NSF CAREER Grant NSF- PHY-0743315. The work of D.J.P. was supported by a Rackham Pre-doctoral Fellowship. The work of A.P. was supported in part by NSF Career Grant NSF-PHY-0743315 and by DOE Grant #DE-FG02-95ER40899. $^{(}$σ squark SI ( χ N → χ N ) max = 6 × 10 − 9 pb$^{(}$ 200 GeV ˜ m$_{s}$ ) 4 , (A.1) $^{(}$σ squark SD ( χ p → χ p ) ) max = 3 × 10 − 4 pb$^{(}$ 200 GeV ˜ m$_{u}$ ) 4 . (A.2) 26