Large-Nc relationships among two-derivative pionless effective field theory couplings

We analyze two-derivative two-nucleon interactions in a combined pionless effective field theory and large-Nc expansion. At leading order in the large-Nc expansion, relationships among low-energy constants emerge. We find these to be consistent with experiment. However, it is critical to correctly address the subtraction-point dependence of the low-energy constants. Here, these results provide additional confidence that the dual-expansion procedure is useful for analyzing low-energy few-body observables.