Large-Nc constraints for elastic dark-matter-light-nucleus scattering in pionless effective field theory

Recent proposals for the use of light nuclei as dark-matter direct detection targets necessitate a strong theoretical understanding of the nuclear physics involved. We perform relevant calculations for dark-matter- light-nucleus scattering in a combined pionless effective field theory and large-N-c expansion, where N-c is the number of quark colors. We include a general set of one-nucleon currents that have been used in other effective theories, as well as novel two-nucleon contact currents. First, we obtain constraints for the relative sizes of the dark-matter couplings to the one- and two-nucleon currents through the large-N-c expansion. Then, we use these constraints to make predictions for the relative sizes of spin-dependent and spin-independent cross sections for dark-matter scattering off of a nucleon, a deuteron, a triton, and helium-3.

Automated summary

Recent proposals for the use of light nuclei as dark-matter direct detection targets require a strong theoretical understanding of nuclear physics. Calculations for dark-matter-light-nucleus scattering are performed using pionless effective field theory and large-N-c expansion. Constraints for the relative sizes of dark-matter couplings to different nucleon currents are obtained through the large-N-c expansion, and used to predict the relative sizes of spin-dependent and spin-independent cross sections for dark-matter scattering off various light nuclei.