Spin-dependent scattering of weakly interacting massive particles in heavy nuclei

We present the results of the first direct calculation of spin-dependent matrix elements relevant for WIMP scattering on heavy nuclear targets in dark matter detectors, including Ge, I, and Xe. We use EMC data on the proton, and nuclear wavefunctions derived in the interacting boson fermion model (IBFM), and find that single-particle shell model estimates are generally within 15% of the exact answer for nucleon spin matrix elements, while quenching of the free particle coefficients in the nuclear environment can reduce them by a further factor of not more than ≈60%.