Ab Initio Structure Factors for Spin-Dependent Dark Matter Direct Detection

We present converged ab initio calculations of structure factors for elastic spin-dependent WIMP scattering off all nuclei used in dark matter direct-detection searches: F-19, Na-23, Al-27, Si-29, Ge-73, I-127, and Xe-129;131. From a set of established two-and three-nucleon interactions derived within chiral effective field theory, we construct consistent WIMP-nucleon currents at the one-body level, including effects from axial vector two-body currents. We then apply the in-medium similarity renormalization group to construct effective valence-space Hamiltonians and consistently transformed operators of nuclear responses. Combining the recent advances of natural orbitals with three-nucleon forces expressed in large spaces, we obtain basis-space converged structure factors even in heavy nuclei. Generally results are consistent with previous calculations but large uncertainties in I-127 highlight the need for further study.

Automated summary

This study presents converged ab initio calculations of structure factors for elastic spin-dependent WIMP scattering off various nuclei used in dark matter direct-detection searches, providing insights into WIMP-nucleon interactions and nuclear responses. The results are generally consistent with previous calculations, but significant uncertainties in I-127 underscore the need for further research.