Quantum Monte Carlo calculations of dark matter scattering off light nuclei

We compute the matrix elements for elastic scattering of dark matter (DM) particles off light nuclei (H-2, H-3, He-3, He-4, and Li-6) using quantum Monte Carlo methods. We focus on scalar-mediated DM-nucleus interactions and use scalar currents obtained to next-to-leading order in chiral effective theory. The nuclear ground states are obtained from a phenomenological nuclear Hamiltonian that includes the Argonne v(18) two-body interaction and the three-body Urbana IX interaction. Within this approach, we study the impact of one- and two-body currents and discuss the size of nuclear uncertainties, including for the first time two-body effects in A = 4 and A = 6 systems. Our results provide the nuclear structure input needed to assess the sensitivity of future experimental searches of (light) dark matter using light nuclei, such as He-3 and He-4.